Guessing game

The problem

Write a program that generates a random number and asks the user to guess what the number is. If the user's guess is higher than the random number,the program should display "Too high, try again." if the user's guess is lower than the random number, the program should display "Too low, try again."

The program should use a loop that repeats until the user correctly guesses the random number. You shall also keep a count of the number of guesses that the user makes. When the user correctly guesses the random number, the program should display the number of usersGuesses. Now add another loop to ask the user if he or she wishes to play the usersGuessing game again. If so, the loop should repeat, otherwise it should terminate.

Breaking it down

Class set up

// Create a Random object.
final static Random rand = new Random();

// max number is the upward bound number
static final int MAX_NUMBER = 10;

Create method to return random number

 * Method should return a random number within the upward bound MAX_NUMBER.
 * @return
static int getRandomNumber () {
    return rand.nextInt(MAX_NUMBER);

Create variables to hold input in program

int usersGuess;
int randomNumber;
int numberOfGuesses; 

Create scanner, ask user for input

Scanner keyboard = new Scanner(;

System.out.println("I'm thinking of a number.");
System.out.print("Guess what it is: ");
usersGuess = keyboard.nextInt();

Call to random number, respond to user's input

numberOfGuesses = 1;

randomNumber = getRandomNumber();

// Respond to the user's usersGuess.
while (usersGuess != randomNumber) {

    if (usersGuess < randomNumber) {
        System.out.println("No, that's too low.");
    } else if (usersGuess > randomNumber) {
        System.out.println("Sorry, that's too high.");

    // Ask again
    System.out.print("Guess again: ");
    usersGuess = keyboard.nextInt();

    // Increment the usersGuess counter.

Display output

System.out.println("Congratulations! You guessed it!");
System.out.println("I was thinking of the number " + randomNumber + ".");
System.out.println("You got it right in " + numberOfGuesses + " guesses.");


I'm thinking of a number.
Guess what it is: 34
Sorry, that's too high.
Guess again: 10
Sorry, that's too high.
Guess again: 5
No, that's too low.
Guess again: 6
No, that's too low.
Guess again: 7
Congratulations! You guessed it!
I was thinking of the number 7.
You got it right in 5 guesses.

Unit tests

public void test_get_random_number () {
    assertThat(GuessingGame.getRandomNumber(), is(lessThan(GuessingGame.MAX_NUMBER)));

Level Up

  • Add input validation, verify they are between the range ie - enter a number between MAX_NUMBER < 0?
  • Allow for a user to choose a different option
  • If a user guesses a number in < some number, display they won some prize while creating a method named 'getPrize'.
  • Identify one flow in this program. Hint: placement of random number?