/in/foo.cc: In function 'int main()':
/in/foo.cc:4:7: warning: unused variable 'a' [-Wunused-variable]
  char a[10],b[10],c[10];
       ^
/in/foo.cc:4:13: warning: unused variable 'b' [-Wunused-variable]
  char a[10],b[10],c[10];
             ^
/in/foo.cc:4:19: warning: unused variable 'c' [-Wunused-variable]
  char a[10],b[10],c[10];
                   ^