/in/foo.cc: In function 'int main()':
/in/foo.cc:5:7: warning: unused variable 'a' [-Wunused-variable]
   int a,b,c,n;
       ^
/in/foo.cc:5:9: warning: unused variable 'b' [-Wunused-variable]
   int a,b,c,n;
         ^
/in/foo.cc:5:11: warning: unused variable 'c' [-Wunused-variable]
   int a,b,c,n;
           ^
/in/foo.cc:5:13: warning: unused variable 'n' [-Wunused-variable]
   int a,b,c,n;
             ^