Armstrong Number Using C

 

 Armstrong Number Using C program

Armstrong Number:

Armstrong number is the number which is equal to sum of cube of its digits.

Example1:

153 is armstrong number.

Explanation:

153=(1*1*1)+(5*5*5)+(3*3*3)

      =(1)+(125)+(27)

     =153

Example2:

354 is not armstrong number.

Explanation:

354=(3*3*3)+(5*5*5)+(4*4*4)

      =27+125+64

     =216

354≠216

C Program:

#include <stdio.h> #include <string.h> int main() { int num; scanf("%d",&num); int n=num; int sum=0,r=0; while(n>0) { r=n%10; sum=sum+(r*r*r); n=n/10; } if(sum==num) { printf("armstrong number"); } else { printf("not an armstrong number"); } return 0; }

Output 1:

Output 2:

From the above program,

 ü Let's take num=153

ü n=num, n=153 

n>0	r=n%10	sum=sum+(r*r*r)	n=n/10
153>0	r=153%10   =3	sum=0+(3*3*3)         =27	n=153/10   =15
15>0	r=15%10   =5	sum=27+(5*5*5)         =27+125         =152	n=15/10   = 1
1>0	r=1%10   =1	sum=152+(1*1*1)         =152+1         =153	n=1/10   =0
0>0 false	doesn't  execute

 ü after the execution of above table, sum= 153.

if(sum==num) { printf("armstrong number"); } else { printf("not an armstrong number"); }

 ü  now it checks the condition sum==num(153==153), since the condition is true, it is armstrong number.