Write a C program to display all the prime numbers between two positive numbers using functions | C programing examples

Write a C program to display all the prime numbers between two positive numbers using functions | Functions in C | C programing examples 

C program to display all the prime numbers between two positive numbers using functions :

#include <stdio.h>

int checkPrimeNumber(int n);

int main() 

{ 

  int n1, n2, i, flag;

 

  printf("Enter a positive integer: ");

  scanf("%d", &n1);

 

   printf("Enter another positive integer: ");

  scanf("%d", &n2);

 

  // swap n1 and n2 if n1 > n2

  if (n1 > n2) {

    n1 = n1 + n2;

    n2 = n1 - n2;

    n1 = n1 - n2;

  }

 

  printf("Prime numbers between %d and %d are: ", n1, n2);

  for (i = n1 + 1; i < n2; ++i)

  { 

    // flag will be equal to 1 if i is prime

    flag = checkPrimeNumber(i);

 

    if (flag == 1) {

      printf("%d ", i);

    }

  }

  return 0;

}

 

// user-defined function to check prime number

int checkPrimeNumber(int n) 

{

  int j, flag = 1;

 

  for (j = 2; j <= n / 2; ++j) 

    {

 

        if (n % j == 0) 

        {

          flag = 0;

          break;

        }

     }

 

  return flag;

}

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