/in/foo.cc: In function 'int main()':
/in/foo.cc:8:27: error: 'n' was not declared in this scope
    8 |  while(cin>>a&&a[0]!='0'&&n--){
      |                           ^
/in/foo.cc:7:6: warning: unused variable 'cnt' [-Wunused-variable]
    7 |  int cnt=1000;
      |      ^~~