Help me in solving LPYAS151 problem

help
,
1

My issue

error

My code

#include<stdio.h>
int main(){
int n,z,u,r=0;
printf("enter the value of n");
scanf("%d",&n);
z=n;
while (z>0){
    r=n%10;
    x=x+r*r*r;
    z=z/10;
}
if(x==z)
printf("the following number is a amstrong number");
else
printf("it is not an amstrong number");
return 0;
}

Learning course: Algorithmic Problem Solving
Problem Link: https://www.codechef.com/learn/course/klu-problem-solving/KLUPS00A/problems/LPYAS151