Why this programm doesn't work?

Question

#include <stdio.h>
#include <math.h>
int
main ()
{
  
int n, i, c,s, b,a,r=0;
scanf ("%d %d", &a, &n);
s=s+a;
for (i=0; i<=n; i++)
{
    b=10*r;
c=a*b;
s=s+c;
    r++ ;
}
printf ("%d", s);
return 0;
}

Answer 1

it is properly working

give a printf to help others to know entering values

Answer 2

yes it is working right once go through again

Answer 3

it's running perfectly. All you need is to declare s=0.

Answer 4

because you should initiate the value of s=0 while declaring variable so variable s can not store the garbage value.