Display Prime Numbers Between Two numbers in c++

C programming is a general-purpose, widely used, high-level programming language. Almost all types of computer programs are written in this language. It is the basic programming language. Write a C program to find prime numbers between two numbers inputted by the user. We will also learn how to display prime numbers between two numbers. Now first we learn about prime numbers.

Required Knowledge

• C print-f and scan-f functions
• For loop in C

Define Prime Number in C Programmings

A prime number is a natural number greater than 1 that is only divisible by either 1 or itself. All numbers other than prime numbers are known as composite numbers. There are infinitely many prime numbers; here is the list of first few prime numbers
2 3 5 7 11 13 17 19 23 29 31 37…

Step 1. In step 1 processors are given to include header file for prime numbers
Step 2. We used main function
Step 3: We have declared variables
Step 4. Two numbers are inputted with the help of the printf and scanf functions.
Step 5. In this step external loop is given here. We use a for loop, which increase their value from 1 to next and so on

Algorithm for Prime Display Prime Numbers Between Two numbers in c++

we just write algorithm for 1 to n number; you can change it according to your need and requirements
Algorithm.
Algorithm to check whether a number is prime or not
Let N be a positive number.

• For every number i, between 2 and N/2 (2 <= i <= N/2), check whether I divide N completely (check If I is a factor of N).
• If (N % i == 0), then N cannot be a prime number.
• If none of the numbers between 2 and N/2 divides N completely, then N is a prime number.

Example of Program

#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
long i,prime,j,n1,n2;
printf("Enter start and end numbers for prime");
scanf("%ld %ld",&n1,&n2);
for(i=n1;i<=n2;i++)
{
 prime=1;
 for(j=2;j<i;j++)
 {
 if(i%j==0)
 {
 prime=0;
 break;
 }
 }
 if(prime==1)
 printf("%ld\t",i);
}
getch();
}

Enter two numbers (intervals): 20
50
Prime numbers between 20 and 50 are 23, 29, 31, 37, 41, 43, and 47.