/in/foo.cc: In function 'int main()':
/in/foo.cc:7:9: warning: 'i' is used uninitialized in this function [-Wuninitialized]
     int i , j= 0;
         ^
/in/foo.cc:30:18: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
     cout << a << ':' << b <<endl;   
                  ^~~