Write a C++ program to generate all the prime numbers between 1 and n, where n is a value

Sure, here is a simple C++ program that generates all the prime numbers between 1 and n:

#include<iostream>
using namespace std;

bool isPrime(int num) {
    if(num <= 1)
        return false;
    for(int i = 2; i * i <= num; i++) {
        if(num % i == 0)
            return false;
    }
    return true;
}

int main() {
    int n;
    cout << "Enter a number: ";
    cin >> n;
    cout << "Prime numbers between 1 and " << n << " are: ";
    for(int i = 2; i <= n; i++) {
        if(isPrime(i))
            cout << i << " ";
    }
    return 0;
}

Here's how it works:

1. The isPrime function checks if a number is prime. It does this by checking if the number is divisible by any number up to its square root. If it is, then it's not a prime number.

2. In the main function, we first ask the user to enter a number n.

3. We then loop from 2 to n (since 1 is not a prime number), and for each number, we check if it's a prime number using the isPrime function.

4. If it is, we print it out.