Question

Write an application that plays "guess the number" as follows: Your program chooses the number to be guessed by selecting a random integer in the range 1 to 1000 . The application displays the prompt Guess a number between 1 and \(1000 .\) The player inputs a first guess. If the player's guess is incorrect, your program should display Too high. Try again. or Too Tow. Try again. to help the player "zero in" on the correct answer. The program should prompt the user for the next guess. When the user enters the correct answer, display Congratulations. You guessed the number!, and allow the user to choose whether to play again. [Note: The guessing technique employed in this problem is similar to a binary search, which is discussed in Chapter 19 Searching, Sorting and Big O.]

Short answer

Generate a random number between 1 and 1000, then loop to prompt the player for guesses, providing hints if the guess is too high or too low, until the correct number is guessed. Congratulate the player on a correct guess and offer to replay the game.

Step-by-step solution

Import a Random Number Generator

First, import the random module, which contains functions to generate random numbers. You will use the random.randint function to select a random integer within the range from 1 to 1000.

Generate a Random Number

Using the random.randint function, generate a random integer between 1 and 1000 and store it in a variable. This will be the number the player has to guess.

Initialize Variables

Initialize any necessary variables, such as a variable to track the player's guess, and a flag to control the game loop.

Write the Game Loop

Create a while loop that continues to prompt the user for a guess until the correct number is guessed. Inside the loop, compare the player's guess to the random number, and give the player a hint to guess higher or lower as appropriate.

Check the Guess

After each guess, check if the guess is too high, too low, or correct. Display an appropriate message for each case.

Ending the Game

Once the player guesses the number correctly, congratulate them and ask if they want to play again. If they do, generate a new random number and continue the game. If not, exit the game.

Implement Replay Option

Provide an option for the user to play again if they wish after a correct guess. This can be achieved with a loop that encloses the bulk of the game code, enabling multiple games to be played in succession.

Key concepts

Random Number Generation

In Java programming, random number generation is a common requirement, especially in game development where unpredictability can significantly enhance gameplay. At the heart of 'guess the number' games lies the ability of the program to generate a number at random that the player must then guess.

To accomplish this, Java provides classes in the java.util package, especially Random and ThreadLocalRandom. The typical method for generating a random integer is using Random.nextInt(int bound), which produces a non-negative random integer less than the specified bound. For example, to get a number between 1 and 1000, you would use nextInt(1000) + 1. This is essential to ensure every number within the range is equally likely to be selected, providing a fair chance to the player.

It is important to instantiate the Random object once and reuse it throughout the game to maintain the randomness of numbers. Frequently re-instantiating the Random object can reduce randomness due to the seeding mechanism of the Random class.

• To add another layer of sophistication to a guessing game, you might use 'seeding' to create a predictable sequence of numbers which might be useful for debugging or repeating scenarios for testing purposes.
• Always ensure the range parameters are correctly set to include all possible values within the gameplay constraints.

Game Loop Implementation

The game loop is a core concept in developing any game, enabling continuous gameplay until a certain exit condition is met. In the classic 'guess the number' game, the game loop allows players to keep guessing until they find the correct number.

To implement a game loop in Java, you generally use a while or do-while loop. This loop repeatedly executes a block of code that gathers user input, processes it, updates the game state, and provides feedback to the player. The loop will continue until the player's guess matches the target number or when the player chooses to exit.

Control statements within the loop dictate the progression of the game. For instance, if a guess is too high, a hint is provided, and the loop continues. Conversely, if the guess is correct, the loop terminates after congratulating the player. It is essential for the loop to include input validation to handle any unexpected user input without crashing the game.

• Incorporate an option to exit the game, ensuring that users are not trapped in an infinite loop.
• Provide clear and concise user feedback for every iteration of the loop to keep the player informed and engaged.

Conditional Statements

Conditional statements are critical in programming—they guide the decision-making process within a program. In 'guess the number' games, they are used to determine whether the player's guess is too high, too low, or correct.

Java uses if, else if, and else statements to execute different blocks of code based on certain conditions. In a number guessing game, an initial if statement might check if the player's guess is lower than the target number. Subsequent else if conditions might check for the opposite case, where the guess is too high. Finally, an else clause can be used to respond to the correct guess.

• Use clear and explicit conditions in your conditional statements to ensure the logic is easily understood and maintainable.
• Remember to validate user input to handle non-numeric input or numbers that are out of bounds, using additional conditional statements.
• Consider edge cases where the guess is exactly on the boundary of your conditions and ensure that your logic accounts for these cases.

Proper implementation of conditional statements results in a responsive and intuitive game experience, providing players with the right prompts and keeping them engaged.