while break sample code in c++

Sure! Here's an example of how to use `while` and `break` in C++:

#include <iostream>
using namespace std;

int main() {
    int num;
    
    while (true) {
        cout << "Enter a number: ";
        cin >> num;
        
        if (num < 0) {
            cout << "Negative numbers are not allowed." << endl;
            break;
        }
        
        cout << "You entered: " << num << endl;
    }
    
    cout << "The loop has ended." << endl;
    return 0;
}

This code prompts the user to enter a number, and if the number is negative, the program will print an error message and exit the loop using the `break` statement. Otherwise, the program will print the number and continue looping until the user enters a negative number. Once the loop has ended, the program will print a message indicating that it has finished.