foo.cc: In function 'int main()':
foo.cc:6:19: warning: variable 'c' set but not used [-Wunused-but-set-variable]
    6 |         int a,b=0,c,d;
      |                   ^
foo.cc:6:21: warning: unused variable 'd' [-Wunused-variable]
    6 |         int a,b=0,c,d;
      |                     ^

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