foo.cc: In function 'int main()':
foo.cc:58:6: warning: 'num1' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int num1,num2,num3,num4;
      ^~~~
foo.cc:58:11: warning: 'num2' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int num1,num2,num3,num4;
           ^~~~
foo.cc:58:16: warning: 'num3' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int num1,num2,num3,num4;
                ^~~~
foo.cc:58:21: warning: 'num4' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int num1,num2,num3,num4;
                     ^~~~