# C++ Program to Calculate Power of a Number

In this article, we will learn to compute power to a number manually, and by using pow() function.

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

This program takes two numbers from the user (a base number and an exponent) and calculates the power.

`Power of a number = baseexponent`

### Example 1: Compute Power Manually

``````#include <iostream>
using namespace std;

int main()
{
int exponent;
float base, result = 1;

cout << "Enter base and exponent respectively:  ";
cin >> base >> exponent;

cout << base << "^" << exponent << " = ";

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

cout << result;

return 0;
}
``````

Output

```Enter base and exponent respectively:  3.4
5
3.4^5 = 454.354```

As we know, the power of a number is the number multiplied by itself repeatedly. For example,

53 = 5 x 5 x 5 = 125

Here, 5 is the base and 3 is the exponent.

In this program, we have calculated the power of a number using a `while` loop.

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

Remember that we have already initialized result as `1` during the beginning of the program.

Let us see how this `while` loop works if `base == 5` and `exponent == 3`.

Iteration result *= base exponent exponent != 0 Execute Loop?
1st `5` `3` `true` Yes
2nd `25` `2` `true` Yes
3rd `125` `1` `true` Yes
4th `625` `0` `false` No

However, 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: Compute power using pow() Function

``````#include <iostream>
#include <cmath>

using namespace std;

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

cout << "Enter base and exponent respectively:  ";
cin >> base >> exponent;

result = pow(base, exponent);

cout << base << "^" << exponent << " = " << result;

return 0;
}
``````

Output

```Enter base and exponent respectively:  2.3
4.5
2.3^4.5 = 42.44```

In this program, we have used the `pow()` function to calculate the power of a number.

Notice that we have included the `cmath` header file in order to use the `pow()` function.

We take the base and exponent from the user.

We then use the `pow()` function to calculate the power. The first argument is the base, and the second argument is the exponent.