C++ Program to Check Prime Number using function

What are Functions ?

Function is a block of statements that performs some operations. All C++ programs have at least one function – function called “main()”. This function is entry-point of your program.

A function declaration tells the compiler about a function’s name, return type, and parameters. A function definition provides the actual body of the function.

Defining a Function : :

The general form of a C++ function definition is as follows:

return_type Function_Name( list of parameters )
{
//function’s body
}

• return_type : suggests what the function will return. It can be void, int, char, some pointer or even a class object.
• Function_Name : is the name of the function, using the function name it is called.
• Parameters : are variables to hold values of arguments passed while function is called. A function may or may not contain parameter list.
• Function body : is he part where the code statements are written.

Below is the source code for C++ Program to Check Prime Number using function which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/*  C++ Program to Check Prime Number using function  */

#include <iostream>
using namespace std;

int checkPrimeNumber(int);

int main()
{
  int n;

  cout << "\nEnter any positive integer :: ";
  cin >> n;

  if(checkPrimeNumber(n) == 0)
    cout <<"\nThe Number [ "<< n << " ] is a prime number.\n";
  else
    cout <<"\nThe Number [ "<< n << " ] is not a prime number.\n";

  return 0;
}

int checkPrimeNumber(int n)
{
  bool flag = false;

  for(int i = 2; i <= n/2; ++i)
  {
      if(n%i == 0)
      {
          flag = true;
          break;
      }
  }
  return flag;
}

OUTPUT : :

/*  C++ Program to Check Prime Number using function  */

Enter any positive integer :: 297

The Number [ 297 ] is not a prime number.

Process returned 0

Above is the source code for C++ Program to Check Prime Number using function which is successfully compiled and run on Windows System.The Output of the program is shown above .