V C++ je řetězec objektem std::string třída, která představuje posloupnost znaků. Můžeme provádět mnoho operací s řetězci, jako je zřetězení, porovnání, konverze atd.
Příklad řetězce C++
Podívejme se na jednoduchý příklad řetězce C++.
#include using namespace std; int main( ) { string s1 = 'Hello'; char ch[] = { 'C', '+', '+'}; string s2 = string(ch); cout<<s1<<endl; cout<<s2<<endl; } < pre> <p>Output:</p> <pre> Hello C++ </pre> <hr> <h2>C++ String Compare Example</h2> <p>Let's see the simple example of string comparison using strcmp() function.</p> <pre> #include #include using namespace std; int main () { char key[] = 'mango'; char buffer[50]; do { cout<>buffer; } while (strcmp (key,buffer) != 0); cout<<'answer is correct!!'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let's see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></'answer></pre></s1<<endl;> Příklad porovnání řetězců C++
Podívejme se na jednoduchý příklad porovnání řetězců pomocí funkce strcmp().
#include #include using namespace std; int main () { char key[] = 'mango'; char buffer[50]; do { cout<>buffer; } while (strcmp (key,buffer) != 0); cout<<\'answer is correct!!\'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let's see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></\'answer> Příklad spojení řetězce C++
Podívejme se na jednoduchý příklad zřetězení řetězců pomocí funkce strcat().
bfs vs dfs
#include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;> Příklad kopírování řetězce C++
Podívejme se na jednoduchý příklad kopírování řetězce pomocí funkce strcpy().
#include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;> Příklad délky řetězce C++
Podívejme se na jednoduchý příklad zjištění délky řetězce pomocí funkce strlen().
#include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;> Řetězcové funkce C++
| Funkce | Popis |
|---|---|
| int porovnat (const string& str) | Používá se k porovnání dvou řetězcových objektů. |
| int délka() | Slouží k nalezení délky řetězce. |
| void swap (řetězec a řetězec) | Slouží k záměně hodnot dvou řetězcových objektů. |
| string substr(int pos,int n) | Vytvoří nový objekt typu řetězec o n znacích. |
| int size() | Vrací délku řetězce v bytech. |
| void resize (int n) | Slouží ke změně velikosti délky řetězce až na n znaků. |
| string& nahradit (int pos, int len, string& str) | Nahrazuje část řetězce, který začíná na pozici znaku pos a zahrnuje znaky len. |
| string& append(const string& str) | Přidá nové znaky na konec jiného řetězcového objektu. |
| char& at (int pos) | Používá se pro přístup k jednotlivému znaku na zadané pozici pozice. |
| int najít(string&str,int pos,int n) | Slouží k nalezení řetězce zadaného v parametru. |
| int find_first_of(string&str,int pos,int n) | Používá se k nalezení prvního výskytu zadané sekvence. |
| int find_first_not_of(string& str,int pos,int n ) | Používá se k vyhledání prvního znaku v řetězci, který se neshoduje s žádným ze znaků zadaných v řetězci. |
| int find_last_of(string&str,int pos,int n) | Používá se k hledání posledního znaku zadané sekvence v řetězci. |
| int najít_poslední_není_of(řetězec&str,int pos) | Hledá poslední znak, který neodpovídá zadané sekvenci. |
| string& insert() | Vloží nový znak před znak označený pozicí poz. |
| int max_size() | Zjistí maximální délku řetězce. |
| void push_back(char ch) | Přidá nový znak ch na konec řetězce. |
| void pop_back() | Odebere poslední znak řetězce. |
| string& assign() | Řetězci přiřadí novou hodnotu. |
| int kopie (řetězec& str) | Zkopíruje obsah řetězce do jiného. |
| char&back() | Vrací odkaz posledního znaku. |
| Iterátor begin() | Vrací odkaz prvního znaku. |
| int kapacita() | Vrátí přidělené místo pro řetězec. |
| const_iterator cbegin() | Ukazuje na první prvek řetězce. |
| const_iterator cend() | Ukazuje na poslední prvek řetězce. |
| void clear() | Odebere všechny prvky z řetězce. |
| const_reverse_iterator crbegin() | Ukazuje na poslední znak řetězce. |
| const_char* data() | Zkopíruje znaky řetězce do pole. |
| bool empty() | Kontroluje, zda je řetězec prázdný nebo ne. |
| string&erase() | Odebere znaky, jak je uvedeno. |
| char& front() | Vrací odkaz na první znak. |
| řetězec&� operátor+=() | Připojí nový znak na konec řetězce. |
| řetězec& operátor=() | Řetězci přiřadí novou hodnotu. |
| char operator[](pos) | Načte znak na zadané pozici pozice. |
| int rfind() | Hledá poslední výskyt řetězce. |
| iterátor end() | Odkazuje na poslední znak řetězce. |
| reverzní_iterátor rend() | Ukazuje na první znak řetězce. |
| void shrink_to_fit() | Snižuje kapacitu a rovná se velikosti struny. |
| char* c_str() | Vrací ukazatel na pole, které obsahuje posloupnost znaků ukončenou nulou. |
| const_reverse_iterator crend() | Odkazuje na první znak řetězce. |
| reverse_iterator rbegin() | Odkazuje na poslední znak řetězce. |
| neplatná rezerva (inr len) | Požaduje změnu kapacity. |
| typ_alokatoru get_allocator(); | Vrátí přidělený objekt spojený s řetězcem. |