 # 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:

## 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.

## 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 Python library.

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

``````base = 3
exponent = -4

result = pow(base, exponent)

`Answer = 0.012345679012345678`