# Python Program to Compute the Power of a Number

In this example, you will learn to compute the power of a number.

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

## 1. Example 1: Calculate power of a number using a while loop

base = 3
exponent = 4

result = 1

while exponent != 0:
result *= base
exponent-=1



Output

Answer = 81


In this program, base and exponent are assigned values 3 and 4 respectively.

Using the while loop, we keep on multiplying the result by base until the exponent becomes zero.

In this case, we multiply result by base 4 times in total, so result = 1 * 3 * 3 * 3 * 3 = 81.

## 2. Example 2: Calculate power of a number using a for loop

base = 3
exponent = 4

result = 1

for exponent in range(exponent, 0, -1):
result *= base



Output

Answer = 81


Here, instead of using a while loop, we’ve used a for loop.

After each iteration, the exponent is decremented by 1, and the result is multiplied by the base exponent number of times.

Both programs above do not work if you have a negative exponent. For that, you need to use the pow() function in the Python library.

## 3. Example 3: Calculate the power of a number using pow() function

base = 3
exponent = -4

result = pow(base, exponent)


Answer = 0.012345679012345678

pow() accepts two arguments: base and exponent. In the above example, 3 raised to the power -4 is calculated using pow().