C program to calculate power of a given number

In C programming, calculating the power of a number means multiplying the base number by itself for a specified number of times (exponent). For example, 3⁴ = 3 × 3 × 3 × 3 = 81. We can implement this using loops or the built-in pow() function.

Syntax

// Manual calculation using loop
result = base^exponent

// Using pow() function
#include <math.h>
double pow(double base, double exponent);

Method 1: Using While Loop

This approach uses a while loop to multiply the base value repeatedly −

#include <stdio.h>

int main() {
    int base, exponent;
    long result = 1;
    int i;
    
    printf("Enter base: ");
    scanf("%d", &base);
    printf("Enter exponent: ");
    scanf("%d", &exponent);
    
    i = exponent;
    while (i != 0) {
        result *= base;
        i--;
    }
    
    printf("%d^%d = %ld<br>", base, exponent, result);
    return 0;
}

Enter base: 3
Enter exponent: 4
3^4 = 81

Method 2: Using pow() Function

The pow() function from math.h library can handle both integer and floating-point calculations −

#include <stdio.h>
#include <math.h>

int main() {
    double base, exponent, result;
    
    printf("Enter base: ");
    scanf("%lf", &base);
    printf("Enter exponent: ");
    scanf("%lf", &exponent);
    
    result = pow(base, exponent);
    
    printf("%.2lf^%.2lf = %.2lf<br>", base, exponent, result);
    return 0;
}

Enter base: 2.5
Enter exponent: 3.0
2.50^3.00 = 15.63

Method 3: Using Recursion

We can also implement power calculation using recursive function −

#include <stdio.h>

int power(int base, int exp) {
    if (exp == 0)
        return 1;
    else
        return base * power(base, exp - 1);
}

int main() {
    int base, exponent, result;
    
    printf("Enter base: ");
    scanf("%d", &base);
    printf("Enter exponent: ");
    scanf("%d", &exponent);
    
    result = power(base, exponent);
    
    printf("%d^%d = %d<br>", base, exponent, result);
    return 0;
}

Enter base: 5
Enter exponent: 3
5^3 = 125

Comparison

Conclusion

For integer calculations, the loop method works well. For real numbers or when performance matters, use the pow() function. The recursive approach is useful for understanding the concept but may cause stack overflow for large exponents.