No output when running program in c++

Question

I wrote a program of Insertion sort in c++ but output screen does not showing any Statement.I am facing this problem in few another program.

This is the code:

#include<iostream>
using namespace std;
int main()
{
    int n;
    int arr[n];

    cout<<"Enter the number of the element of the Array:";
    cin>>n;

    cout<<"Enter the element of the Array:";
    for(int i=0;i<n;i++){
        cin>>arr[i];
    }

    for(int i=0;i<n;i++){
        int current=arr[i];
        int j=i-1;
        while(arr[j]>current && j>=0){
            arr[j+1]=arr[j];
            j--;
        }
        arr[j+1]=current;
    }

    for(int i=0;i<n;i++){
        cout<<arr[i]<<" ";
    }cout<<endl;
    return 0;
}

question from:https://stackoverflow.com/questions/65830676/no-output-when-running-program-in-c

Answer 1

You are using the value of n before it has a value. Change your code to this

int n;          // n does not have a value
cout<<"Enter the number of the element of the Array:";
cin>>n;         // n gets value here
int arr[n];     // n is used here

You cannot use any variable before it has a value. That's a fundamental rule of C++.