# Field Manual for Hackers

## java - Print all the prime numbers between two given numbers.

1. import java.util.Scanner;

class Test{

public static void main(String ar[])
{

Scanner sc=new Scanner(System.in);
int num1,num2,count=0,num;
System.out.println("Enter Two Numbers");
num1=sc.nextInt();
num2=sc.nextInt();

for(int j=num1;j<=num2;j++){

num=j;
for(int i=1;i<=num;i++){
if(num%i==0)
count++;
}
if(count==2){System.out.println(num+" is a Prime Number");}
else{System.out.println(num+" is Not a Prime Number");}
count=0;
}
}
}

2. import java.util.Scanner;

class Test
{

public static void main(String ar[])
{

int i=2,flag=0,upper_limit,lower_limit;
System.out.print("Enter the lower limit: ");
Scanner w=new Scanner(System.in);
lower_limit=w.nextInt();
System.out.print("Enter the upper limit: ");
upper_limit=w.nextInt();
System.out.print("The prime numbers between these two numbers are: ");
while(lower_limit<upper_limit)
{
flag=0;
i=2;
while(i<lower_limit)
{
if(lower_limit%i==0)
flag=1;
i++;
}
if(flag!=1)
{
System.out.print(lower_limit+"\t");
}
lower_limit++;
}
}
}

3. import java.util.Scanner;
{
public static void main(String args[])
{int new1,t=0;
Scanner scan=new Scanner(System.in);
System.out.println("Enter the Number from where you want to start");
int Start=scan.nextInt();
System.out.println("Enter the Number from where you want to end");
int End=scan.nextInt();
for(int i=Start;i<=End;i++)
{ new1=i;t=0;
for(int j=1;j<=new1;j++)
{
if(new1%j==0)
{
t++;
}
}
if(t==2)
{
System.out.println("Prime Number="+new1);

}
}

}
}

4. import java.util.Scanner;
class PrimeN
{
public static void main(String Args[])
{
Scanner sc=new Scanner(System.in);
System.out.println("enter the lower limit");
int a=sc.nextInt();
System.out.println("enter the upper limit");
int b=sc.nextInt();
int count=0;
int num,i;
for(i=a;i<b;i++)
{
num=i;
for(int j=1;j<=num;j++)
{
if(num%j==0)
count++;
}
if(count==2)
System.out.println(num+"is prime number");
else
System.out.println(num+"is not a prime number");
count=0;
}
}
}

5. import java.util.Scanner;

public class prime1
{
public static void main(String ar[])
{
Scanner scan = new Scanner(System.in);
int a,b,num;
int count;
System.out.println("enter the first no");
a = scan.nextInt();
System.out.println("enter the second no");
b=scan.nextInt();
for(int i=a;i<b;i++)
{ num=i;
count=0;
for(int j=1;j<=num;j++)
{
if(num%j==0)
{
count++;
}
}
if(count==2)
{
System.out.println("Prime Number="+num);

}
}

}
}

output:

enter the first no
2
enter the second no
13
Prime Number=2
Prime Number=3
Prime Number=5
Prime Number=7
Prime Number=11

6. package forloop;
import java.util.*;
public class Twoprime
{
public static void main(String args[])
{
int i,j,num1,num2,count=0,num;
System.out.println("enter two numbers");
Scanner sc=new Scanner(System.in);
num1=sc.nextInt();
num2=sc.nextInt();
for(i=num1;i<=num2;i++)
{
num=i;
for(j=2;j<=num/2;j++)
{
if(num%j==0)
{
count=1;
break;
}
}
if(count==0)
{
System.out.println("Prime Number is "+num);
}
count=0;
}
}
}

7. import java.util.Scanner;
class Prime1{
public static void main(String ar[]){
Scanner obj=new Scanner(System.in);
int num1,num2,i,num;
System.out.println("enter the nos");
num1=obj.nextInt();
num2=obj.nextInt();
for(num=num1;num<=num2;num++){
for(i=2;i<=num/2;i++){
if(num%2!=0){
System.out.println(num);
break;
}
}}
}
}

8. import java.util.*;
class Prime{
public static void main(String ar[]){
Scanner s=new Scanner(System.in);
int i=2,flag=0,n1,n2;
System.out.print("Enter number1: ");
n1=s.nextInt();
System.out.print("Enter number2: ");
n2=s.nextInt();
System.out.print("The prime numbers between"+n1+"and"+2+"are: ");
while(n1<n2)
{
flag=0;
i=2;
while(i<n1)
{
if(n1%i==0)
flag=1;
i++;
}
if(flag!=1)
{
System.out.print(n1+" ");
}
n1++;
}
}
}

9. import java.util.Scanner;

class Prime{

public static void main(String ar[]){
int num1,num2,n,count=0;
Scanner scan=new Scanner(System.in);

System.out.println("Enter Number 1:");
num1=scan.nextInt();
System.out.println("Enter Number 2:");
num2=scan.nextInt();
for(int j=num1;j<=num2;j++){
n=j;
for(int i=1;i<=n;i++){
if(n%i==0)
count++;
}
if(count==2){
System.out.println(n+" is a prime number");
}
else{
System.out.println(n+" is not a prime number");
}
count=0;
}
}
}