V této části napíšeme Java programy pro určení mocniny čísla. Chcete-li získat mocninu čísla, vynásobte číslo jeho exponentem.
Příklad:
Předpokládejme, že základ je 5 a exponent je 4. Chcete-li získat mocninu čísla, vynásobte jej samo sebou čtyřikrát, tj. (5 * 5 * 5 * 5 = 625).
Jak určit mocninu čísla?
- Základ a exponent by měly být načteny nebo inicializovány.
- Vezměte další proměnnou sílu a nastavte ji na 1, abyste výsledek uložili.
- Vynásobte základ výkonem a výsledek uložte do výkonu pomocí smyčky for nebo while.
- Opakujte krok 3, dokud se exponent nerovná nule.
- Vytiskněte výstup.
Metody k nalezení mocniny čísla
Existuje několik způsobů, jak určit sílu čísla:
podtrhnout pomocí css
- Použití Java pro smyčku
- Používání Javy při Loop
- Použití rekurze
- Použití metody Math.pow().
- Použití bitové manipulace
1. Použití Java pro smyčku
Smyčku for lze použít k výpočtu mocniny čísla opakovaným násobením základu sebou samým.
PowerOfNumber1.java
public class PowerOfNumber1 { public static void main(String[] args) { int base = 2; int exponent = 3; int result = 1; for (int i = 0; i <exponent; i++) { result *="base;" } system.out.println(base + ' raised to the power of exponent is result); < pre> <p> <strong>Output:</strong> </p> <pre> 2 raised to the power of 3 is 8 </pre> <h3>2. Using Java while Loop</h3> <p>A while loop may similarly be used to achieve the same result by multiplying the base many times.</p> <p> <strong>PowerOfNumber2.java</strong> </p> <pre> public class PowerOfNumber2 { public static void main(String[] args) { int base = 2; int exponent = 3; int result = 1; int power=3; while (exponent > 0) { result *= base; exponent--; } System.out.println(base + ' raised to the power of ' + power + ' is ' + result); } } </pre> <p> <strong>Output:</strong> </p> <pre> 2 raised to the power of 3 is 8 </pre> <h3>3. Using Recursion:</h3> <p>Recursion is the process of breaking down an issue into smaller sub-problems. Here's an example of how recursion may be used to compute a number's power.</p> <p> <strong>PowerOfNumber3.java</strong> </p> <pre> public class PowerOfNumber3 { public static void main(String[] args) { int base = 2; int exponent = 3; int result = power(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is ' + result); } public static int power(int base, int exponent) { if (exponent == 0) { return 1; } else { return base * power(base, exponent - 1); } } } </pre> <p> <strong>Output:</strong> </p> <pre> 2 raised to the power of 3 is 8 </pre> <h3>4. Using Math.pow() Method</h3> <p>The java.lang package's Math.pow() function computes the power of an integer directly.</p> <p> <strong>PowerOfNumber4.java</strong> </p> <pre> public class PowerOfNumber4 { public static void main(String[] args) { double base = 2.0; double exponent = 3.0; double result = Math.pow(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is ' + result); } } </pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 3.0 is 8.0 </pre> <h3>Handling Negative Exponents:</h3> <p>When dealing with negative exponents, the idea of reciprocal powers might be useful. For instance, x^(-n) equals 1/x^n. Here's an example of dealing with negative exponents.</p> <p> <strong>PowerOfNumber5.java</strong> </p> <pre> public class PowerOfNumber5 { public static void main(String[] args) { double base = 2.0; int exponent = -3; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { if (exponent >= 0) { return calculatePositivePower(base, exponent); } else { return 1.0 / calculatePositivePower(base, -exponent); } } static double calculatePositivePower(double base, int exponent) { double result = 1.0; for (int i = 0; i <exponent; i++) { result *="base;" } return result; < pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of -3 is: 0.125 </pre> <h3>Optimizing for Integer Exponents:</h3> <p>When dealing with integer exponents, you may optimize the calculation by iterating only as many times as the exponent value. It decreases the number of unneeded multiplications.</p> <p> <strong>PowerOfNumber6.java</strong> </p> <pre> public class PowerOfNumber6 { public static void main(String[] args) { double base = 2.0; int exponent = 4; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; for (int i = 0; i <exponent; i++) { result *="base;" } return result; < pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 4 is: 16.0 </pre> <h3>5. Using Bit Manipulation to Calculate Binary Exponents:</h3> <p>Bit manipulation can be used to better improve integer exponents. To do fewer multiplications, an exponent's binary representation might be used.</p> <p> <strong>PowerOfNumber7.java</strong> </p> <pre> public class PowerOfNumber7 { public static void main(String[] args) { double base = 2.0; int exponent = 5; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; while (exponent > 0) { if ((exponent & 1) == 1) { result *= base; } base *= base; exponent >>= 1; } return result; } } </pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 5 is: 32.0 </pre> <hr></exponent;></pre></exponent;></pre></exponent;> 2. Používání Javy ve smyčce
Smyčku while lze podobně použít k dosažení stejného výsledku mnohonásobným vynásobením základu.
PowerOfNumber2.java
jvm
public class PowerOfNumber2 { public static void main(String[] args) { int base = 2; int exponent = 3; int result = 1; int power=3; while (exponent > 0) { result *= base; exponent--; } System.out.println(base + ' raised to the power of ' + power + ' is ' + result); } } Výstup:
2 raised to the power of 3 is 8
3. Použití rekurze:
Rekurze je proces rozdělení problému na menší dílčí problémy. Zde je příklad toho, jak lze rekurzi použít k výpočtu síly čísla.
PowerOfNumber3.java
public class PowerOfNumber3 { public static void main(String[] args) { int base = 2; int exponent = 3; int result = power(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is ' + result); } public static int power(int base, int exponent) { if (exponent == 0) { return 1; } else { return base * power(base, exponent - 1); } } } Výstup:
2 raised to the power of 3 is 8
4. Použití metody Math.pow().
Funkce Math.pow() balíčku java.lang počítá přímo sílu celého čísla.
123 film
PowerOfNumber4.java
public class PowerOfNumber4 { public static void main(String[] args) { double base = 2.0; double exponent = 3.0; double result = Math.pow(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is ' + result); } } Výstup:
2.0 raised to the power of 3.0 is 8.0
Zpracování záporných exponentů:
Při práci se zápornými exponenty může být užitečná myšlenka recipročních mocnin. Například x^(-n) se rovná 1/x^n. Zde je příklad zacházení se zápornými exponenty.
PowerOfNumber5.java
public class PowerOfNumber5 { public static void main(String[] args) { double base = 2.0; int exponent = -3; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { if (exponent >= 0) { return calculatePositivePower(base, exponent); } else { return 1.0 / calculatePositivePower(base, -exponent); } } static double calculatePositivePower(double base, int exponent) { double result = 1.0; for (int i = 0; i <exponent; i++) { result *="base;" } return result; < pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of -3 is: 0.125 </pre> <h3>Optimizing for Integer Exponents:</h3> <p>When dealing with integer exponents, you may optimize the calculation by iterating only as many times as the exponent value. It decreases the number of unneeded multiplications.</p> <p> <strong>PowerOfNumber6.java</strong> </p> <pre> public class PowerOfNumber6 { public static void main(String[] args) { double base = 2.0; int exponent = 4; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; for (int i = 0; i <exponent; i++) { result *="base;" } return result; < pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 4 is: 16.0 </pre> <h3>5. Using Bit Manipulation to Calculate Binary Exponents:</h3> <p>Bit manipulation can be used to better improve integer exponents. To do fewer multiplications, an exponent's binary representation might be used.</p> <p> <strong>PowerOfNumber7.java</strong> </p> <pre> public class PowerOfNumber7 { public static void main(String[] args) { double base = 2.0; int exponent = 5; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; while (exponent > 0) { if ((exponent & 1) == 1) { result *= base; } base *= base; exponent >>= 1; } return result; } } </pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 5 is: 32.0 </pre> <hr></exponent;></pre></exponent;> Optimalizace pro celočíselné exponenty:
Při práci s celočíselnými exponenty můžete optimalizovat výpočet iterací pouze tolikrát, kolikrát je hodnota exponentu. Snižuje počet nepotřebných násobení.
PowerOfNumber6.java
java long to int
public class PowerOfNumber6 { public static void main(String[] args) { double base = 2.0; int exponent = 4; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; for (int i = 0; i <exponent; i++) { result *="base;" } return result; < pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 4 is: 16.0 </pre> <h3>5. Using Bit Manipulation to Calculate Binary Exponents:</h3> <p>Bit manipulation can be used to better improve integer exponents. To do fewer multiplications, an exponent's binary representation might be used.</p> <p> <strong>PowerOfNumber7.java</strong> </p> <pre> public class PowerOfNumber7 { public static void main(String[] args) { double base = 2.0; int exponent = 5; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; while (exponent > 0) { if ((exponent & 1) == 1) { result *= base; } base *= base; exponent >>= 1; } return result; } } </pre> <p> <strong>Output:</strong> </p> <pre> 2.0 raised to the power of 5 is: 32.0 </pre> <hr></exponent;> 5. Použití bitové manipulace k výpočtu binárních exponentů:
Bitovou manipulaci lze použít k lepšímu vylepšení celočíselných exponentů. Chcete-li provést méně násobení, může být použita binární reprezentace exponentu.
PowerOfNumber7.java
public class PowerOfNumber7 { public static void main(String[] args) { double base = 2.0; int exponent = 5; double result = calculatePower(base, exponent); System.out.println(base + ' raised to the power of ' + exponent + ' is: ' + result); } static double calculatePower(double base, int exponent) { double result = 1.0; while (exponent > 0) { if ((exponent & 1) == 1) { result *= base; } base *= base; exponent >>= 1; } return result; } } Výstup:
2.0 raised to the power of 5 is: 32.0