ROOT Jupyter Notebook cin not working/getting skipped

[Aiskon]

Here’s a simple piece of C++ code:

int i,j,n;
n=8;
cout<<"Enter n:"<<endl;
cin>>n;
for(i=0;i<n;i++)
{
    for(j=(n-i);j>0;j--)
    {
        cout<<"*";
    }
    printf("\n");
}

The output that the above code gives is:

Enter n:
********
*******
******
*****
****
***
**
*

This is done on a C++ based ROOT Kernel on Jupyter Notebook. As you can see, the code does not throw any error at all, yet just takes n=8; and skips over the cin input line (if I remove n=8;, then the output is just “Enter n:”). I have tried to use scanf, getline and getch and all seem to have the same result in the end.

So, does anyone know why this might be happening?

[etejedor]

Hello,

I’m afraid that is not supported in the C++ Jupyter notebook at the moment, and the cin >> n line does not ask for user input. This would probably need some Jupyter widget to be implemented and intercept the use of cin. The same that exists in a Python notebook for e.g. n = input().