Question

C++

Your goal is to ask the user for a number and to determine if that number is a prime number. Use a function to determine if the number is prime. Your program should have the following:

 The name of the program should be Assignment 6.

 3 comment lines (description of the program, author, and date).

 Ask the user for an integer. Store this result in a variable with an appropriate name. (1 point)

 Write a function that has an integer parameter and determines if that integer is a prime number. A prime number is divisible by itself and 1. This function should return true if the number is prime and false if the number is not prime. Give this function an appropriate name. (5 points)

 Call the function and save the result in a variable. (2 points)

 Display the result of whether the user entered number is prime or not prime. (2 points)

Answer 1

#include<iostream>

using namespace std;

// return true if n is prime

bool isPrime(int n)

{

    // if no is not prime

    if( n < 2 )

        return false;

   

    // 2 is the only even prime number

    if( n == 2 )

        return 2;

       

    // any even number except 2 is not prime

    if( n % 2 == 0 )

        return false;

       

    int i;

    for( i = 3 ; i < n ; i += 2 )

        // if n is divisible by 3

        if( n % i == 0 )

            return false;

   

    // f no is prime

    return true;

}

int main()

{

    int n;

    cout<<"Enter a number : ";

    cin>>n;

   

    if( isPrime(n) )

        cout<<"\n"<<n<<" is prime.";

    else

        cout<<"\n"<<n<<" is not prime.";

       

    return 0;

}

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Sample Output