C++ Exercises: Find the last prime number occur before the entered number

C++ For Loop: Exercise-8 with Solution

Write a program in C++ to find the last prime number that occurs before the entered number.

Pictorial Presentation:

Sample Solution :-

C++ Code :

#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;
}

Sample Output:

 Find the last prime number occurs before the entered number:          
-----------------------------------------------------------------      
Input a number to find the last prime number occurs before the number: 
50                                                                     
47 is the last prime number before 50  

Flowchart:

C++ Code Editor:

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