foo.c: In function 'main':
foo.c:6:2: error: 'cin' undeclared (first use in this function)
  cin>>n>>x;
  ^
foo.c:6:2: note: each undeclared identifier is reported only once for each function it appears in
foo.c:5:19: warning: unused variable 'cx' [-Wunused-variable]
     int n,x,cnt=0,cx=0;
                   ^