Prime numbers within 2 bounds

[maynardjk13]

Hi!

I'm almost done with this program, but I have a problem: Whenever it displays the prime numbers, it throws in non prime numbers that are odd (like 9 and 15) Here is the code so far.

/*
  File: isprime.cpp
  Created by: Ricardo Renta
  Creation Date: 11/8/11
  Synopsis:
  This program reads in a minimum and maximum integer greater than 1
  and returns all primes between the minimum and maximum.
*/

#include <iostream>
#include <cmath>

using namespace std;

// FUNCTION PROTOTYPE FOR read_range
void read_range( int& imin, int& imax);


// FUNCTION PROTOTYPE FOR is_prime
bool is_prime (int k); //boolean prototype for true and false


// DO NOT MODIFY THE MAIN ROUTINE IN ANY WAY
int main()
{
  int imin(0), imax(0);

  // Read in range
  read_range(imin, imax);

  // Print prime numbers
  cout << "Primes:";
  for (int k = imin; k <= imax; k++) {
    if (is_prime(k)) 
      { 
        cout << "  " << k; 
      }
  }
  cout << endl;

  return 0;
}

// DEFINE FUNCTION read_range() HERE:
void read_range(int& imin, int& imax)
{ 
  cout << "Enter a minimum and maximum value:";
  cin >> imin >> imax;
  
  while (imin < 2 || imax < 2 && imin > imax)
    { cout << "The minimum and maximum values must be at least 2. Please try again."<< endl;
      cin >> imin >> imax;
    }
}
  
  
  


// DEFINE FUNCTION is_prime() HERE:
bool is_prime(int k)
{

  for (int i=2; i<=k-1; i++)
    {
      if (k%i==0)
	{return false;}
      
      else 
	{return true;}
    }
     
}

I know that the problem is in the function definition, specifically the for loop. Could I get a point in the right direction? Thank you in advance!

[mrnutty]

You need to put line 69-70 in line 72.

bool isPrime(int num){
 for(int i = 2; i < num; ++i){
     if(num % i == 0) return false;
 }
 return true;
}