/in/foo.cc: In function 'int main()':
/in/foo.cc:8:21: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int tmp;while(b)tmp=a%b,a=b,b=tmp;
                  ~~~^~~~
/in/foo.cc:11:5: note: 'a' was declared here
 int main(){
     ^~~~
/in/foo.cc:8:21: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int tmp;while(b)tmp=a%b,a=b,b=tmp;
                  ~~~^~~~
/in/foo.cc:11:5: note: 'b' was declared here
 int main(){
     ^~~~
/in/foo.cc:30:10: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<a/gcd<<endl<<b/gcd<<endl;
          ^~~