Question

C++

Create a program that checks whether a number is a prime number and displays its factors if it is not a prime number.

Console

Prime Number Checker

Please enter an integer between 1 and 5000: 5

5 is a prime number.

Try again? (y/n): y

Please enter an integer between 1 and 5000: 6

6 is NOT a prime number.

It has 4 factors: 1 2 3 6

Try again? (y/n): y

Please enter an integer between 1 and 5000: 200

200 is NOT a prime number.

It has 12 factors: 1 2 4 5 8 10 20 25 40 50 100 200

Try again? (y/n): n

Bye!

Specifications

• A prime number is divisible by two factors (1 and itself). For example, 7 is a prime number because it is only divisible by 1 and 7.
• Assume that the user will enter a valid integer.
• If the user enters an integer that’s not between 1 and 5000, the program should display an error message.
• If the number is a prime number, the program should display a message.
• If the number is not a prime number, the program should display a message. Then, it should display the number of factors for the number and a list of those factors.
• Store the factors for each number in a vector.

Answer 1

#include <iostream>
using namespace std;

int isPrime(int n)
{
    for (int i = 2; i < n; i++) {
        if (n % i == 0) {
            return 0;
        }
    }
    return 1;
}


int main(){
   int n;
   char ch = 'y';
   
   while(ch=='y'){
      cout<<"Please enter an integer between 1 and 5000: ";
      cin>>n;
      
      if(isPrime(n)){
             cout<<n<<" is a prime number."<<endl;
      }
      else{
          int count = 0;
          for(int i = 1;i<=n;i++){
              if(n%i==0){
                  count++;
              }
          }
          cout<<"It has "<<count<<" factors: ";
          for(int i = 1;i<=n;i++){
              if(n%i==0){
                  cout<<i<<" ";
              }
          }
          cout<<endl;
             cout<<n<<" is NOT a prime number."<<endl;
      }
      cout<<"Try again? (y/n): ";
      cin>>ch;
      //cin>>ch;
   }
   cout<<"Bye!";
   return 0;
}