Question

Write a method square0fAsterisks that displays a solid square (the same number of rows and columns) of asterisks whose side is specified in integer parameter side. For example, if side is 4, the method should display Incorporate this method into an application that reads an integer value for side from the user and outputs the asterisks with the squareOfAster'sks method:

Short answer

Create a method to print rows and columns of asterisks using nested loops.

Step-by-step solution

Define the Method Signature

We need to create a method named `squareOfAsterisks` that takes a single integer parameter `side`. This integer will determine the number of rows and columns for the square of asterisks.

Implement the Loop to Create Rows

Within the `squareOfAsterisks` method, create a for-loop that iterates `side` times. Each iteration of this loop will represent one row of the square.

Implement Nested Loop for Columns

Inside the outer loop, create another for-loop that also iterates `side` times. This nested loop will be responsible for printing `side` asterisks in a single line, creating a column for each row.

Print Asterisks and Newline

In each iteration of the inner loop, print a single asterisk without moving to the next line (use `print`). After the inner loop completes, print a newline character (use `println`) to move to the next row.

Create Main Method

In the main method of your application, prompt the user to input an integer for the `side` using a Scanner. Pass this input parameter to `squareOfAsterisks` to display the square of asterisks.

Key concepts

Method Definition

In Java, defining a method involves specifying its name, parameters, and what the method is supposed to do. In this exercise, we define a method named `squareOfAsterisks`. This method takes an integer parameter called `side`. This parameter determines both the number of rows and columns of the square of asterisks.
To define a method, you'll start with a method signature. For `squareOfAsterisks`, the signature looks like this:

• public static void squareOfAsterisks(int side)

The `public static` part means the method can be called from anywhere (public) and belongs to the class rather than an instance of the class (static). The `void` keyword indicates that this method does not return a value.
The method implementation follows the signature. Inside the method, you will write the code that actually performs the task of printing a square of asterisks.

Nested Loops

Nested loops are used in programming to reiterate over elements multiple times, usually within a multidimensional structure. In this exercise, we need to use nested loops to create both the rows and columns of the square. First, an outer loop runs `side` times to create each row.

• for (int i = 0; i < side; i++) { - This loop handles the vertical iteration.
• Inside it, another loop runs, for example, for (int j = 0; j < side; j++) {, which takes care of the horizontal iteration.

The nested (inner) loop is responsible for printing the asterisks in a single row. The outer loop ensures a new line is started after each row is printed.
This concept allows you to construct a grid or matrix-like pattern, such as our asterisk square.

User Input Handling

One of the essential features of interactive Java applications is handling user input. In this exercise, you prompt the user to enter the integer size of the asterisk square. This is accomplished through the `Scanner` class, which is part of Java's standard library. Here’s how you handle user input:

• First, create a new instance of Scanner: Scanner input = new Scanner(System.in);
• Prompt the user with a print statement: System.out.print("Enter the size of the square: ");
• Retrieve the user input: int side = input.nextInt();

The `Scanner` class reads user input from the command line, allowing your program to react based on what the user enters. Don't forget to close the scanner at the end using input.close() to free system resources!

Output Formatting

Output formatting in Java deals with how information is presented to the user. In this exercise where we print a square of asterisks, output formatting ensures the asterisks align correctly to visually form a square. Ensuring proper formatting involves understanding how to control the cursor in the console. By using the `print` function for individual asterisks without line breaks, you can form a continuous row:

• System.out.print("*"); - This outputs an asterisk `*` without advancing to a new line.
• After completing one row, a new line starts with System.out.println();

Each row and column are printed sequentially, ensuring the width and height are equal, corresponding to the input parameter `side`. Proper formatting keeps the output clear and accurate, helping users intuitively understand the result.