# C++ program to display prime numbers between two intervals using function

In this article, you will learn how to print the prime numbers between two intervals using the function in the c++ programming language.

You should have knowledge of the following topics in c++ programming to understand this program:

- C++ functions
- C++

function**main** - C++

loop statement**for** - C++

condition statement**if** - C++

statement**continue** - C++

object**cin** - C++

object**cout**

In this program, we are using a

function to find the prime numbers of the given two intervals.**user-defined**

### Source Code

```
// C++ program to display prime numbers between two intervals using function
#include <bits/stdc++.h>
using namespace std;
// @custom function to find the prime numbers between intervals
int GeneratePrimeNumbers(int low_number, int high_number) {
int flag, temp;
// this will swap the value of intervals between each other
// if low_number is greater then high_number
if (low_number > high_number) {
temp;
temp = low_number;
low_number = high_number;
high_number = temp;
}
cout << "\nThe prime numbers between " << low_number << " and " << high_number << " are: ";
for (int i = low_number; i <= high_number; i++) {
flag = 0;
// this will ignore numbers less than 2
if (i <= 1) {
continue;
}
// if low_number is a non-prime number, flag will be 1
for (int j = 2; j <= i / 2; j++) {
if (i % j == 0) {
flag = 1;
break;
}
}
if (flag == 0)
cout << i << " ";
}
cout << "\n";
return 0;
}
// @driver function to call & print the primer numbers
int main() {
int low_number, high_number;
cout << "Enter the two intervals:\n";
cin >> low_number >> high_number;
// @call the custom function to print the numbers
GeneratePrimeNumbers(low_number, high_number);
return 0;
}
```

### Output

`Enter the two intervals:`

10 40

`The prime numbers between 10 and 40 are: 11 13 17 19 23 29 31 37`

**Note**: We swapped the value of the interval between each other if

is greater than **low_number**

.**high_number**

### Explanation

In this given program we used a **user-defined** function to find the primer numbers between two intervals.

so first we have taken two inputs

and **16**

from the user then these values pass to this function **35**

after making the calculation it returned the list of prime numbers.**GeneratePrimeNumbers()**