
January 25th, 2013, 07:17 AM
#1
can someone explain whats going on
here is a full working program to check a number for primeness
i need an expert who can explain it for me particularly the section //print results
what is if(is_prime) mean.
#include <iostream>
#include <cmath>
using namespace std;
int main() {
int n; // Number to test for primeness
int i; // Loop counter
int is_prime = true; // Boolean flag...
// Assume true for now.
// Get a number from the keyboard.
cout << "Enter a number and press ENTER: ";
cin >> n;
// Test for prime by checking for divisibility
// by all whole numbers from 2 to sqrt(n).
i = 2;
while (i <= sqrt(n)) { // While i is <= sqrt(n),
if (n % i == 0) // If i divides n,
is_prime = false; // n is not prime.
i++; // Add 1 to i.
}
// Print results
if (is_prime)
cout << "Number is prime." << endl;
else
cout << "Number is not prime." << endl;
system("PAUSE");
return 0;
}

January 25th, 2013, 08:03 AM
#2
Re: can someone explain whats going on
Originally Posted by TalkTime
here is a full working program to check a number for primeness
Next time, please use code tags when posting code. Your code is almost unreadable without using them.
i need an expert who can explain it for me particularly the section //print results
what is if(is_prime) mean.
What part of that statement is confusing you? The if()? The is_prime? The is_prime is either true or false, and the if() statement executes if it is true.
Regards,
Paul McKenzie
Posting Permissions
 You may not post new threads
 You may not post replies
 You may not post attachments
 You may not edit your posts

Forum Rules

Click Here to Expand Forum to Full Width
This is a CodeGuru survey question.
Featured
