foo.cc: In function 'int main()':
foo.cc:7:20: warning: unused variable 'k' [-Wunused-variable]
    7 |         long n,i,j,k,tmp,x1,x2;
      |                    ^
foo.cc:7:22: warning: unused variable 'tmp' [-Wunused-variable]
    7 |         long n,i,j,k,tmp,x1,x2;
      |                      ^~~
foo.cc:7:26: warning: unused variable 'x1' [-Wunused-variable]
    7 |         long n,i,j,k,tmp,x1,x2;
      |                          ^~
foo.cc:7:29: warning: unused variable 'x2' [-Wunused-variable]
    7 |         long n,i,j,k,tmp,x1,x2;
      |                             ^~

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