Java Program to Generate Random Numbers in Specified Range

Java Program to Generate Random Numbers in Specified Range using for loop

In java programming, Math.random is used to generate random double number between 0 and 1.

This java program is used to generate the random numbers based on range user input and required numbers count user input.

import java.util.Scanner;	
import java.lang.*;

public class RandomNumber {

	public static void main(String args[]) {
	  Scanner in = new Scanner(System.in); 
	  System.out.println("Random Numbers");
	  System.out.println("--------------");
	  System.out.print("Enter range: ");
	  String strRange = in.nextLine();
	  String[] rangeVal = strRange.split("-");
	  if (rangeVal.length !=2){
		  System.out.println("Invalid range format!");
		  return;
	  }
	  int min = Integer.parseInt(rangeVal[0].trim());
	  int max = Integer.parseInt(rangeVal[1].trim());
	  if (max<=min){
		  System.out.println("Invalid range format!");
		  return;  
	  }
	  System.out.print("Enter required random numbers count: ");
	  int count = in.nextInt();
	  System.out.println("Random Numbers in Range ('"+strRange+"')");
	  for(int i=0;i<count;i++){
		  int randomNum = (((int)(Math.random()*100)%(max-min))+min);
		  System.out.print(randomNum + "\t");
	  }
	}
 } 

D:\Java_Programs>javac RandomNumber.java
D:\Java_Programs>java RandomNumber 
Random Numbers
--------------
Enter range: 10-20
Enter required random numbers count: 25
Random Numbers in Range ('10-20')
17	14	16	13	19	13	
13	19	14	13	13	12	
16	11	10	17	16	14	
15	19	13	17	10	12	
10	

Java Program to Generate Random Numbers in Specified Range using while loop

import java.util.Scanner;	
import java.lang.*;

public class RandomNumber {

	public static void main(String args[]) {
	  Scanner in = new Scanner(System.in); 
	  System.out.println("Random Numbers");
	  System.out.println("--------------");
	  System.out.print("Enter range: ");
	  String strRange = in.nextLine();
	  String[] rangeVal = strRange.split("-");
	  if (rangeVal.length !=2){
		  System.out.println("Invalid range format!");
		  return;
	  }
	  int min = Integer.parseInt(rangeVal[0].trim());
	  int max = Integer.parseInt(rangeVal[1].trim());
	  if (max<=min){
		  System.out.println("Invalid range format!");
		  return;  
	  }
	  System.out.print("Enter required random numbers count: ");
	  int count = in.nextInt();
	  System.out.println("Random Numbers in Range ('"+strRange+"')");
	  int i=0;
	  while (i<count){
		  int randomNum = (((int)(Math.random()*100)%(max-min))+min);
		  System.out.print(randomNum + "\t");
		  i++;
	  }
	}
 } 

D:\Java_Programs>javac RandomNumber.java
D:\Java_Programs>java RandomNumber 
Random Numbers
--------------
Enter range: 15-24
Enter required random numbers count: 25
Random Numbers in Range ('15-24')
20	22	21	18	15	15	
18	20	21	17	16	19	
23	23	21	17	19	19	
18	20	19	21	19	22	
18