foo.cc: In function 'int main()':
foo.cc:5:8: warning: unused variable 'a' [-Wunused-variable]
    5 |  int x,a=0,s=0,c,i=1;
      |        ^
foo.cc:9:4: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
    9 |   c*=i;
      |   ~^~~

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