/in/foo.cc: In function 'int main()':
/in/foo.cc:20:23: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
 while(a % k != 0 || b % k !=0 ) 
                     ~~^~~
/in/foo.cc:20:9: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
 while(a % k != 0 || b % k !=0 ) 
       ~~^~~