## Before writing a program we should know what is Armstrong number.

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, 371 is an Armstrong number since 3**3 + 7**3 + 1**3 = 371.

# include < stdio.h >

# include < conio.h >

int main()

{

int num = 0, s, r, t;

clrscr();

printf ( ” \n Enter any number : ” );

scanf ( ” %d “, &num );

t = num;

s = 0;

while ( num > 0 )

{

r = num % 10;

s = s + ( r * r * r );

num = num / 10;

}

if ( s == t )

{

printf ( ” \n %d Is an Armstrong number.”, t );

}

else

{

printf ( ” \n %d Is not an Armstrong number.”, t );

}

return 0;

}

**Output :**

Enter any number : 153

153 Is an Armstrong number.