Hey i guuys, i researched for this topic and there were some close titles to this but none exactly helped me.

I need a write a boolean function named IsPrime that takes and integer as argument and returns true if it is. I have to demonstrate it in a full program. I know i have to use the % operator but im still kinda lost.

I was thinking using the % operator to see if there is a remainder, and if it does then return false.

Im really new to this language and my professor is going really quick. Please help

What do you need help with? Maybe this will get you started.

#include <iostream>

using namespace std;

bool isPrime(int number){
  bool isPrimeNumber = false;
  //do logic here

  return isPrimeNumber;
}

int main(){
  cout << boolalpha << "Is 5 prime : " << isPrime(5) << endl; //should be true
  cout << boolalpha << "Is 97 prime: " << isPrime(97) << endl; //should be true
  cout << boolalpha << "Is 27 prime: " << isPrime(27) << endl; //should be false

 return 0;
}

Edited 4 Years Ago by firstPerson: n/a

What do you need help with? Maybe this will get you started.

#include <iostream>

using namespace std;

bool isPrime(int number){
  bool isPrimeNumber = false;
  //do logic here

  return isPrimeNumber;
}

int main(){
  cout << boolalpha << "Is 5 prime : " << isPrime(5) << endl; //should be true
  cout << boolalpha << "Is 97 prime: " << isPrime(97) << endl; //should be true
  cout << boolalpha << "Is 27 prime: " << isPrime(27) << endl; //should be false

 return 0;
}

Edited 4 Years Ago by firstPerson: n/a

Hey i guuys, i researched for this topic and there were some close titles to this but none exactly helped me.

I helped with (or at least followed) many of the prime number programs here. If memory serves, and it does, almost all will help you.

You have basically 2 things to do:
1) test a value for prime. Reread a few of those unhelpful threads and you'll learn how to figure out if a number is prime or not.
2) take that code and turn it into your function.

thank you guys. I have been trying with what you told me. Thanks for the code, it give me a heads up to start. This is what i got and im still receiving an error.

#include <iostream>
#include <iomanip>


using namespace std;

bool isPrime(int number){
  int remainder;
  bool isPrimeNumber = false;
  cout<<"Please enter a number"<<endl;
  cin>>number;
  remainder = number % number;
      if (remainder=0){
          bool isPrimeNumber = true;
      }
      else {

      }

  //do logic here

  return isPrimeNumber;
}

int main(){
  cout << boolalpha << "Is 5 prime : " << isPrime(number) << endl; 

  system("pause");

 return 0;
}

Thanks

Edited 3 Years Ago by Dani: Formatting fixed

Still receives an error? We didn't know you had an error in the first place?

Your really need to learn to ask for help properly. The info you gave so far has been totally incomplete -- meaning we can't tell what's happening because you didn't tell us.

You need to read this, especially #1, #2, #4, #5:

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Why do you have your number variable checking for a remainder on itself? Any number divided by itself is going to have no remainder, so your check is always going to come back true.

This article has been dead for over six months. Start a new discussion instead.