I need help with a program, here is the question.

An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 153 is an Armstrong number since 1^3 + 5^3 + 3^3 = 153. Create a function named isArmstrong that takes one positive integer number as argument and returns a Boolean variable which is true if the number is an Armstrong number and return false otherwise. Use this function isArmstrong in your main( ) function to print all Armstrong numbers in the range of 100 and 999.