/in/foo.cc: In function 'int main()':
/in/foo.cc:9:6: warning: unused variable 'a' [-Wunused-variable]
  int a[100][100];
      ^
/in/foo.cc:10:6: warning: unused variable 'b' [-Wunused-variable]
  int b[100][100];
      ^
/in/foo.cc:11:6: warning: unused variable 'c' [-Wunused-variable]
  int c[100][100];
      ^