C Primer Plus®, Third Edition

A Loop Example Using a Function Return Value

For the last example in this chapter, you'll design a function that calculates the result of raising a number to an integer power. (For the serious number-cruncher, the math.h library provides a more powerful power function called pow() that allows floating-point exponents.) The three main tasks in this exercise are devising the algorithm for calculating the answer, expressing the algorithm in a function that returns the answer, and providing a convenient way of testing the function.

First, let's look at an algorithm. Keep the function simple by restricting it to positive integer powers. Then, if you want to raise a to the b power, you have to multiply a times itself b times. This is a natural ...