foo.cc: In function 'int max(int, int)':
foo.cc:8:8: warning: variable 'f' set but not used [-Wunused-but-set-variable]
  int m,f,v;
        ^
foo.cc: In function 'int main()':
foo.cc:24:13: warning: variable 'c' set but not used [-Wunused-but-set-variable]
     int a,b,c,d;
             ^
foo.cc:24:15: warning: unused variable 'd' [-Wunused-variable]
     int a,b,c,d;
               ^
foo.cc: In function 'int max(int, int)':
foo.cc:19:3: warning: 'v' is used uninitialized in this function [-Wuninitialized]
  f=v;
  ~^~

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