fastread homefastrread library fastread menu

C++ : Check Whether a Number can be Express as Sum of Two Prime Numbers

Tutorial by:Manisha Dubey      Date: 2016-06-18 04:31:36

❰ Previous Next ❱

This program takes a positive integer from user and checks whether that number can be expressed as the sum of two prime numbers. If that number can be expressed as sum of two prime numbers then, that number is expressed as sum of two prime numbers in output. To perform this task, a user-defined function is created to check prime number.


#include <iostream>
using namespace std;
int check_prime(int n);
int main()
{
    int n, i, flag=0;
    cout << "Enter a positive  integer: ";
    cin >> n;
    for(i=2; i<=n/2; ++i)
    {
        if (check_prime(i)==0)
        {
            if ( check_prime(n-i)==0)
            {
                cout << n << " = " << i << " + " << n-i << endl;
                flag=1;
            }

        }
    }
    if (flag==0)
      cout << n << " can't be expressed as sum of two prime numbers.";
    return 0;
}
int check_prime(int n) /*check prime number*/
{
  int i, flag=0;
  for(i=2;i<=n/2;++i)
  {
      if(n%i==0)
      {
          flag=1;
          break;
      }
  }
  return flag;
}

Output


Enter a positive integer: 34
34 = 3 + 31
34 = 5 + 29
34 = 11 + 23
34 = 17 + 17

❰ Previous Next ❱


C++

Submit Your Thought, Tutorial, Articls etc.

Submit Your Information India's Number one online promotion website