Chapter 5a - Random

Random Introduction

import java.util.Random;
class Main {
   public static void main(String args[]) {
       
       Random rand = new Random(); //creates object of class Random which is used to generate random number
       int randomNum = rand.nextInt(4); //generates random numbers
       System.out.println(randomNum);
   }
}

🧪 Try the code out~!

👀

Coin Simulation

import java.util.Scanner;
import java.util.Random;
class Main {
   public static void main(String args[]) {
       Scanner scan = new Scanner(System.in);
       Random rand = new Random(); //creates object of class Random which is used to generate random number
       System.out.println("This is a simulation of a coin toss.");
       System.out.println("Tossing coin now...\n");
       int randomNum = rand.nextInt(2); //generates random numbers 0 & 1
       if (randomNum == 0) {
           System.out.println("HEADS...\n");
       } else {
           System.out.println("TAILS...\n");
       }
   }
}

🧪 Try the code out~!

(i) Does the user provide any input here?

Yes

No

(ii) What are the possible outputs?

Heads or Tails

1 and 2's

Yes and No's

(iii) Which line of code requires that the random module be imported?

Scanner scan = new Scanner(System.in);

Random rand = new Random()

(iv) What are the values stored by randomNum ?

0 and 1 only

2 and 3

(v) What module is required to generate random numbers?

import java.util.Scanner

import java.util.Random

Exercise: Team Selection

tip

• Create a program to randomnly assign someone in either blue or red team

---

🙋‍♀️ expected

Introduce Random Module - Formatting

import java.math.RoundingMode; 
import java.text.DecimalFormat;
class Main {
 public static void main(String[] args) {
   for(int count = 0; count< 5; count++){
     System.out.println(Math.random());
   }
  }
}

🧪 Try the code out~!

Formatting Random

import java.math.RoundingMode;
import java.text.DecimalFormat;
class Main {
public static void main(String[] args) {
    DecimalFormat df = new DecimalFormat("0.00");
    for(int count = 0; count< 5; count++){
    double d=Math.random();
    System.out.println(df.format(d)); 
  }
 }
}

🧪 Try the code out~!

Exercise