/in/foo.c: In function 'main':
/in/foo.c:7:22: error: '$right' undeclared (first use in this function); did you mean 'right'?
  scanf("%d %d",&left,$right);
                      ^~~~~~
                      right
/in/foo.c:7:22: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:28:6: error: redeclaration of 'i' with no linkage
  int i,j;
      ^
/in/foo.c:8:13: note: previous declaration of 'i' was here
  int a[100],i,max=0;
             ^
/in/foo.c:29:5: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  if(b[a[i]%10]=b[a[j]%10])
     ^
/in/foo.c:29:4: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
  if(b[a[i]%10]=b[a[j]%10])
    ^
/in/foo.c:14:13: warning: unused variable 'm' [-Wunused-variable]
  int b[100],m;
             ^