C Program to Calculate the Power of a Number

Example on how to calculate the power of a number if the exponent is an integer. Also you will learn to compute the power using pow() function.

To understand this example, you should have the knowledge of following C programming topics:

Power of a number

The program below takes two integers from the user (a base number and an exponent) and calculates the power.

For example: In case of 23

  • 2 is the base number
  • 3 is the exponent
  • And, the power is equal to 2*2*2

Example #1: Power of a Number Using while Loop

#include <stdio.h>
int main()
{
    int base, exponent;

    long long result = 1;

    printf("Enter a base number: ");
    scanf("%d", &base);
    printf("Enter an exponent: 4");
    scanf("%d", &exponent);

    while (exponent != 0)
    {
        result *= base;
        --exponent;
    }

    printf("Answer = %lld", result);

    return 0;
}

Output

Enter a base number: 3
Enter an exponent: 4
Answer = 81

The above technique works only if the exponent is a positive integer.

If you need to find the power of a number with any real number as an exponent, you can use pow() function

Example #2: Power Using pow() Function

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

int main()
{
    double base, exponent, result;

    printf("Enter a base number: ");
    scanf("%lf",&base);

    printf("Enter an exponent: ");
    scanf("%lf",&exponent);

    // calculates the power
    result = pow(base,exponent);

    printf("%.1lf^%.1lf = %.2lf", base, exponent, result);

    return 0;
}

Output

Enter a base number: 2.3
Enter an exponent: 4.5
2.3^4.5 = 42.44