The goto statement
goto statement unconditionally transfers control to the statement with the given label.
A label is an identifier followed by a colon:
ngoto label;
nlabel: do something;
#include <iostream.h>
void main(){
  int n, sum=0;
  loop:
cin >> n;
if (n != 0) goto nonzero;
goto print;
nonzero: sum += n;
goto loop;
  print: cout << sum;
}