foo.cc: In function 'int main()':
foo.cc:22:8: warning: unused variable 'a' [-Wunused-variable]
  int n,a,b,c,d;
        ^
foo.cc:22:10: warning: unused variable 'b' [-Wunused-variable]
  int n,a,b,c,d;
          ^
foo.cc:22:12: warning: unused variable 'c' [-Wunused-variable]
  int n,a,b,c,d;
            ^
foo.cc:22:14: warning: unused variable 'd' [-Wunused-variable]
  int n,a,b,c,d;
              ^

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