/in/foo.c: In function 'main':
/in/foo.c:15:6: error: 'j' undeclared (first use in this function)
   if(j>i)
      ^
/in/foo.c:15:6: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:9:7: warning: unused variable 'x' [-Wunused-variable]
   int x=sqrt(i);
       ^