Co je pole?

Pole je typ datové struktury, která ukládá pevnou velikost homogenní kolekce dat. Stručně řečeno, můžeme říci, že pole je sbírka proměnných stejného typu.

slunečný deol věk

Chceme-li například deklarovat 'n' počet proměnných, n1, n2...n., vytvoříme-li všechny tyto proměnné jednotlivě, stane se to velmi zdlouhavým úkolem. V takovém případě vytvoříme pole proměnných stejného typu. Ke každému prvku pole lze přistupovat pomocí indexu prvku.

Nejprve se podívejme, jak předat funkci jednorozměrné pole.

 #include void getarray(int arr[]) { printf(&apos;Elements of array are : &apos;); for(int i=0;i<5;i++) { printf('%d ', arr[i]); } int main() arr[5]="{45,67,34,78,90};" getarray(arr); return 0; < pre> <p>In the above program, we have first created the array <strong>arr[]</strong> and then we pass this array to the function getarray(). The <strong>getarray()</strong> function prints all the elements of the array arr[].</p> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c.webp" alt="Return an Array in C"> <p> <strong>Passing array to a function as a pointer</strong> </p> <p>Now, we will see how to pass an array to a function as a pointer.</p> <pre> #include void printarray(char *arr) { printf(&apos;Elements of array are : &apos;); for(int i=0;i<5;i++) { printf('%c ', arr[i]); } int main() char arr[5]="{&apos;A&apos;,&apos;B&apos;,&apos;C&apos;,&apos;D&apos;,&apos;E&apos;};" printarray(arr); return 0; < pre> <p>In the above code, we have passed the array to the function as a pointer. The function <strong>printarray()</strong> prints the elements of an array.</p> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-2.webp" alt="Return an Array in C"> <h4>Note: From the above examples, we observe that array is passed to a function as a reference which means that array also persist outside the function.</h4> <p> <strong>How to return an array from a function</strong> </p> <p> <strong>Returning pointer pointing to the array</strong> </p> <pre> #include int *getarray() { int arr[5]; printf(&apos;Enter the elements in an array : &apos;); for(int i=0;i<5;i++) { scanf('%d', &arr[i]); } return arr; int main() *n; n="getarray();" printf('
elements of array are :'); for(int i="0;i&lt;5;i++)" printf('%d', n[i]); 0; < pre> <p>In the above program, <strong>getarray()</strong> function returns a variable &apos;arr&apos;. It returns a local variable, but it is an illegal memory location to be returned, which is allocated within a function in the stack. Since the program control comes back to the <strong>main()</strong> function, and all the variables in a stack are freed. Therefore, we can say that this program is returning memory location, which is already de-allocated, so the output of the program is a <strong>segmentation fault</strong> .</p> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-3.webp" alt="Return an Array in C"> <p> <strong>There are three right ways of returning an array to a function:</strong> </p> <ul> <tr><td>Using dynamically allocated array</td>  </tr><tr><td>Using static array</td>  </tr><tr><td>Using structure</td>  </tr></ul> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-4.webp" alt="Return an Array in C"> <p> <strong>Returning array by passing an array which is to be returned as a parameter to the function.</strong> </p> <pre> #include int *getarray(int *a) { printf(&apos;Enter the elements in an array : &apos;); for(int i=0;i<5;i++) { scanf('%d', &a[i]); } return a; int main() *n; a[5]; n="getarray(a);" printf('
elements of array are :'); for(int i="0;i&lt;5;i++)" printf('%d', n[i]); 0; < pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-5.webp" alt="Return an Array in C"> <p> <strong>Returning array using malloc() function.</strong> </p> <pre> #include #include int *getarray() { int size; printf(&apos;Enter the size of the array : &apos;); scanf(&apos;%d&apos;,&amp;size); int *p= malloc(sizeof(size)); printf(&apos;
Enter the elements in an array&apos;); for(int i=0;i<size;i++) { scanf('%d',&p[i]); } return p; int main() *ptr; ptr="getarray();" length="sizeof(*ptr);" printf('elements that you have entered are : '); for(int i="0;ptr[i]!=&apos;&apos;;i++)" printf('%d ', ptr[i]); 0; < pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-6.webp" alt="Return an Array in C"> <p> <strong>Using Static Variable</strong> </p> <pre> #include int *getarray() { static int arr[7]; printf(&apos;Enter the elements in an array : &apos;); for(int i=0;i<7;i++) { scanf('%d',&arr[i]); } return arr; int main() *ptr; ptr="getarray();" printf('
elements that you have entered are :'); for(int i="0;i&lt;7;i++)" printf('%d ', ptr[i]); < pre> <p>In the above code, we have created the variable <strong>arr[]</strong> as static in <strong>getarray()</strong> function, which is available throughout the program. Therefore, the function getarray() returns the actual memory location of the variable &apos; <strong>arr</strong> &apos;.</p> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-7.webp" alt="Return an Array in C"> <p> <strong>Using Structure</strong> </p> The structure is a user-defined data type that can contain a collection of items of different types. Now, we will create a program that returns an array by using structure.<p></p> <pre> #include #include struct array { int arr[8]; }; struct array getarray() { struct array y; printf(&apos;Enter the elements in an array : &apos;); for(int i=0;i<8;i++) { scanf('%d',&y.arr[i]); } return y; int main() struct array x="getarray();" printf('elements that you have entered are :'); for(int i="0;x.arr[i]!=&apos;&apos;;i++)" printf('%d ', x.arr[i]); 0; < pre> <p> <strong>Output</strong> </p> <img src="//techcodeview.com/img/c-tutorial/16/return-an-array-c-8.webp" alt="Return an Array in C"> <hr></8;i++)></pre></7;i++)></pre></size;i++)></pre></5;i++)></pre></5;i++)></pre></5;i++)></pre></5;i++)>