/in/foo.cc: In function 'int main()':
/in/foo.cc:11:15: warning: 'num' may be used uninitialized [-Wmaybe-uninitialized]
   11 |         cout<<num<<endl;
      |               ^~~
/in/foo.cc:4:17: note: 'num' was declared here
    4 |         int a,b,num;
      |                 ^~~