/in/foo.cc: In function 'int main()':
/in/foo.cc:10:9: warning: statement has no effect [-Wunused-value]
   for(x1; x1<x; x1++) 
         ^
/in/foo.cc:13:3: warning: 'x1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(x1!=x)  
   ^~