C++ Programs

C++ Program to Display or Print Prime Numbers Between a Range or an Interval

by Amit Rawat · Published June 1, 2019 · Updated June 1, 2019

In this program, we will learn how to display or print the Prime Numbers between a given range using the C++ programming language.

I have already discussed how to check whether a number is prime or not in previous posts. So, check it out for better understanding.

I will be discussing different programs

Between an Interval.
In Range 1 to N

C++ Programming Code to Display or Print Prime Numbers Between a Range or an Interval

In both the programs below, I have used the different approaches in the inner for loop.

In one, I have traversed until half of the number (i/2). And in other, I have traversed till the square root of the number (sqrt(i)).

Between an Interval

In this program, user is asked to give the start and end of the range or interval.

And then I apply the for loop in that range and check every number in between the range including the ends also whether they are a prime number or not.

Code:-

#include<iostream>

using namespace std;

int main(){
	int start, end;
    bool isPrime;

	cout << "Enter starting number of the interval : ";
	cin >> start;
	cout << "Enter ending number of the interval : ";
	cin >> end;
	cout << "Prime Numbers Between " << start << " and " << end << " : " << endl;

	for(int i=start; i<=end; i++){
        isPrime = true;

        if(i <= 1){
            isPrime = false;
        }else{
            for(int j = 2; j <= i/2; j++){  
                if(i % j == 0){  
                    isPrime = false;  
                    break;  
                }  
            }
        }
  
        if (isPrime)  
            cout << i << " ";  
    }
    cout << endl;

    return 0;
}

Output:-

Enter starting number of the interval : 5
Enter ending number of the interval : 55
Prime Numbers Between 5 and 55 :
5 7 11 13 17 19 23 29 31 37 41 43 47 53

In Range 1 to N

In this program, I have asked for only the end of the range.

And then with the help of for loop, numbers are checked.

Code:-

#include<iostream>
#include<math.h>

using namespace std;

int main(){
	int  end;
    bool isPrime;

	cout << "Enter the end of the range : ";
	cin >> end;
	cout << "Prime Numbers Between 1" << " and " << end << " : " << endl;

	for(int i=2; i<=end; i++){
        isPrime = true;

        for(int j = 2; j <= sqrt(i); j++){  
            if(i % j == 0){  
                isPrime = false;  
                break;  
            }  
        }
  
        if (isPrime)  
            cout << i << " ";  
    }
    cout << endl;

    return 0;
}