foo.cc: In function 'int main()':
foo.cc:8:23: warning: unused variable 'k' [-Wunused-variable]
    8 |         long n, i, j, k, tmp, x1, x2;
      |                       ^
foo.cc:8:26: warning: unused variable 'tmp' [-Wunused-variable]
    8 |         long n, i, j, k, tmp, x1, x2;
      |                          ^~~
foo.cc:8:31: warning: unused variable 'x1' [-Wunused-variable]
    8 |         long n, i, j, k, tmp, x1, x2;
      |                               ^~
foo.cc:8:35: warning: unused variable 'x2' [-Wunused-variable]
    8 |         long n, i, j, k, tmp, x1, x2;
      |                                   ^~

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