/in/foo.cc: In function 'int main()':
/in/foo.cc:5:12: warning: variable 'd' set but not used [-Wunused-but-set-variable]
  int a,b,c,d;
            ^
/in/foo.cc:6:7: warning: 'a' is used uninitialized in this function [-Wuninitialized]
  d=100*a+10*b+c;
    ~~~^~
/in/foo.cc:6:12: warning: 'b' is used uninitialized in this function [-Wuninitialized]
  d=100*a+10*b+c;
          ~~^~
/in/foo.cc:6:3: warning: 'c' is used uninitialized in this function [-Wuninitialized]
  d=100*a+10*b+c;
  ~^~~~~~~~~~~~~