Prime Numbers Between Two Numbers

C++ Programs

In the previous program (Prime and Composite Numbers) the user had entered any number and the output stated whether it was a prime or a composite number. 
In this program, the user will enter any two different numbers and the output will be all the prime numbers between those two numbers.

For this, I am using user-defined-function in which I will be using for-loops and if-statements.

Code:

#include<iostream.h>

#include<conio.h>

void prime(int a,int b)

{

int i,j,k;

for(i=a;i<=b;i++)

 {

  k=0;

  for(j=2;j<=i/2;j++)

   {

    if(i%j==0)

    k=1;

   }

  if(k==0)

  cout<<i<<"\n";

 }

}

void main()

{

clrscr();

int a,b;

cout<<"\t"<<"\t"<<"Prime numbers between two numbers"<<"\n";

cout<<"From: ";

cin>>a;

cout<<"To: ";

cin>>b;

prime(a,b);

getch();

}

Output:

First Run:

Second Run:

Note: For finding composite numbers between any two numbers apply the same code but with just a slight change. In the prime function, in the outermost loop, the condition for the if statement has to be changed, i.e.,:

void prime(int a,int b)

{

int i,j,k;

for(i=a;i<=b;i++)

 {

  k=0;

  for(j=2;j<=i/2;j++)

   {

    if(i%j==0)

    k=1;

   }

  if(k==1)

  cout<<i<<"\n";

 }

}

It gives all the composite numbers between any two numbers.

For any queries or suggestions please comment !