What's the problem in the outer while loop?

Question

#include<iostream>
using namespace std;
int main()
{
  int x,y,n=0,ch='y';
  while(ch=='y')//problem loop
  {
    gno:
    x=rand()%9999+1000;
    y=x;
    n=0;
    while(y>0)
    {
      y=y/10;
      n++;
      if(n>3&&n<3)
        goto gno;
    }
    cout<<x<<endl;
    cin>>ch;
  }
  return 0;
}

Whenever I run the above code, it displays one random number as it should. But after that even when I enter the value of ch as "y" (without the quotes, of course!) the while loop marked as "problem loop" just doesn't continue. Ya, I get it that it's some kind of a runtime error but can anyone please specify what is causing this problem, and by making what exact changes to the code will let me run it successfully?

Because `ch` is an `int`. Change it to `char`. – Eraklon Mar 28 '20 at 15:10 — Eraklon, Mar 28 '20 at 15:10
When is `n<3&&n>3` ever true? – Scott Hunter Mar 28 '20 at 15:10 — Scott Hunter, Mar 28 '20 at 15:10

score 3 · Answer 1 · answered Mar 28 '20 at 15:16

You defined ch as an int, which means that cin will interpret the input as an integer and read it into ch. You can observe that this happens when you enter 121 and the code continues. To fix your issue, just change

int x,y,n=0,ch='y';

into

int x,y,n=0;
char ch='y';

Also, you have an if statement that will never happen, so you might as well get rid of the if(n>3&&n<3) and the goto. Keep in mind that goto is bad.

What's the problem in the outer while loop?

1 Answers1