/in/foo.cc: In function 'int main()':
/in/foo.cc:11:12: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   11 |   for(i=0;i<strlen(a);i++){
      |           ~^~~~~~~~~~
/in/foo.cc:5:18: warning: unused variable 'n' [-Wunused-variable]
    5 |  int red,green,i,n,j;
      |                  ^
/in/foo.cc:5:20: warning: unused variable 'j' [-Wunused-variable]
    5 |  int red,green,i,n,j;
      |                    ^