Write a program in C++ to find the last prime number occur before the entered number

#include <iostream>
using namespace std;
int main()
{
    int num1, ctr = 0;
    cout << "\n\n Find the last prime number occurs before the entered number:\n";
    cout << "-----------------------------------------------------------------\n";
    cout << " Input a number to find the last prime number occurs before the number: ";
    cin >> num1;
    for (int n = num1 - 1; n >= 1; n--) 
    {
        for (int m = 2; m < n; m++) 
        {
            if (n % m == 0)
                ctr++;
        }
        if (ctr == 0) 
        {
            if (n == 1) 
            {
                cout << "no prime number less than 2";
                break;
            }
            cout << n << " is the last prime number before " << num1 << endl;
            break;
        }
        ctr = 0;
    }
    return 0;
}