/in/foo.cc: In function 'int main()':
/in/foo.cc:10:12: error: 'i' was not declared in this scope
  for(int c=i-1;c>=1;c--)
            ^
/in/foo.cc:5:13: warning: unused variable 'c' [-Wunused-variable]
  int n[100],c;
             ^