/in/foo.cc: In function 'int gcd(int, int)':
/in/foo.cc:6:12: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  while(r=a%b){
            ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:15:6: warning: unused variable 'a' [-Wunused-variable]
  int a[102];
      ^