foo.cc: In function 'int main()':
foo.cc:6:10: warning: variable 'b' set but not used [-Wunused-but-set-variable]
    int a,b,c,d,x,y,z;
          ^
foo.cc:6:12: warning: variable 'c' set but not used [-Wunused-but-set-variable]
    int a,b,c,d,x,y,z;
            ^
foo.cc:6:14: warning: variable 'd' set but not used [-Wunused-but-set-variable]
    int a,b,c,d,x,y,z;
              ^
foo.cc:15:7: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
    y=y*10+a;
      ~^~~

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