C++ Programming Code Examples C++ > Mathematics Code Examples Program to Display Armstrong Number Between Two Intervals Program to Display Armstrong Number Between Two Intervals Example to find all Armstrong numbers between two integers (entered by the user) using loops and if...else statement. This program asks user to enter two integers and displays all Armstrong numbers between the given interval. If you don't know how to check whether a number is Armstrong or not in programming then, this program may seem little complex. In this program, it is assumed that, the user always enters smaller number first. This program will not perform the task intended if user enters larger number first. You can add the code to swap two numbers entered by user if user enters larger number first to make this program work properly. In this program, each number between the interval is taken and stored in variable num. Then, each digit of the number is retrieved in digit and cubed (^3). The cubed result is added to the cubed result of the last digit sum. Finally, when each digit is traversed, sum is compared with the original number i. If they are equal, the number is an armstrong number. #include <iostream> using namespace std; int main() { int number1, number2, i, num, digit, sum; cout << "Enter first number: "; cin >> number1; cout << "Enter second number: "; cin >> number2; cout << "Armstrong numbers between " << number1 << " and " << number2 << " are: " << endl; for(i = number1; i <= number2; i++) { sum = 0; num = i; for(; num > 0; num /= 10) { digit = num % 10; sum = sum + digit * digit * digit; } if(sum == i) { cout << i << endl; } } return 0; }