power – Exponentiation – Computer Science by Example

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power – Exponentiation

Write a program that performs integer exponentiation of a base b to the power of n.

bⁿ = 1 × b × b × … × b where b is repeated n times

for example

2⁵ = 1 × 2 × 2 × 2 × 2 × 2 = 32

Segment, square, cube and tesseract

For this exercise, you should consider that 0⁰ = 1.

Input and output

Input will contain several lines each with two integers b and n where

-1000 ≤ b ≤ 1000

0 ≤ n ≤ 30

For each line of input, output should contain a corresponding line with a single integer indicating the value of bⁿ.

Input will be given so that

-1 000 000 000 < bⁿ < 1 000 000 000

Example input

2 5
5 2

Example output

32
25

The `power` function

Your program should contain a power function that takes two integers and returns an integer. The first integer argument should be the base and the second the exponent. Please refer to the information for your chosen language:

C prototype: int power(int b, int n);
Haskell type: power :: Int -> Int -> Int
Python definition: def power(b, n):
C++ prototype: int power(int b, int n);
C# prototype: public static int Power(int b, int e)
Java definition: public static int power(int b, int e) in a public class Power
JavaScript definition: function power(b, e)
Lua definition: function power (b, e)
Ruby definition: def power(b, e)

You should perform the exponentiation as a series of multiplications. For this exercise, you should restrain from using your programming languages' built-in exponentiation functions.

Specifically for this exercise when using Python, JavaScript, Lua or Ruby, avoid using sys.exit(), process.exit(), os.exit() or exit, as your program is appended with some extra assertions in one of the test sets.

Scoring

1/6: works for the above example albeit in an incorrect format
2/6: works for the above example in the correct format
3/6: works for other examples
4/6: has good performance
5/6: works for edge cases
6/6: implements the power function

try first: factorial power1

try next: fibonacci

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