Friday, June 18, 2021
Home coding Write a program to check armstrong number.

# Write a program to check armstrong number.

Given a number we have to find whether number is armstrong or not.

So what is Armstrong number?

Armstrong Number is a number which is equal to the sum of cube of its digit.

for example-0,1,153,371 all are armstrong number.

Example:

``````input:1
output:true

input :9:
output:false``````

Logic:

``Logic behind this question is to just find all the digit of number then calculate cube of all digits. then resultant output is armstrong number.``

```#include<iostream>
using namespace std;
int main()
{
int num;
cout<<"Enter a number : "<<endl;
cin>>num;
int armstrong=0;
int original_number=num;
int pal=0;
while(num>0)
{
int rem=num%10;
armstrong+=rem*rem*rem;
num=num/10;
}
if(armstrong==original_number)
{
cout<<"number is armstrong "<<endl;
}
else
{
cout<<"number is not armstrong"<<endl;
}

}```

Output:

```Enter a number : 371
number is armstrong ```

Time Complexity-O(N)

Space Complexity-0(1)

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