An integer number is called **Armstrong number** if sum of the cubes of its digits is equal to the number itself. For example:

370 is an armstrong number because:

370 = 3*3*3 + 7*7*7 + 0*0*0 = 27 + 343 + 0 = 370

## Example: Check Armstrong Number using For loop

To understand this program, you should have the knowledge of for loop and if-else statement.

#include <iostream> using namespace std; int main() { int num, sum = 0, digit; cout<<"Enter a positive integer: "; cin>>num; for(int temp=num; temp!=0;){ digit = temp % 10; sum = sum +(digit * digit * digit); temp = temp/10; } if(sum == num) cout<<num<<" is an Armstrong number."; else cout<<num<<" is not an Armstrong number."; return 0; }

**Output:**

Enter a positive integer: 370 370 is an Armstrong number.

You can also use while loop instead of for loop to check the Armstrong number:

**Replace this part of the code:**

for(int temp=num; temp!=0;){ digit = temp % 10; sum = sum +(digit * digit * digit); temp = temp/10; }

**with this:**

int temp = num; while(temp != 0) { digit = temp % 10; sum = sum +(digit * digit * digit); temp = temp/10; }

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