Question

Write a function that displays at the left margin of the screen a solid square of asterisks whose side is specified in integer parameter side. For example, if side is \(4,\) the function displays the following:

Short answer

Use nested loops: outer loop for rows and inner loop for printing asterisks in each row.

Step-by-step solution

Understanding the Problem

We need to write a function that takes an integer as a parameter and displays a square made of asterisks. The width and height of the square should match the integer parameter.

Designing the Function

First, we need to create a function definition that accepts an integer parameter called 'side'. This integer represents the number of asterisks on each side of the square.

Implementing the Loop for Rows

Inside the function, we use a 'for' loop to iterate 'side' times. Each iteration represents a row of the square.

Creating Each Line

For each row, use another 'for' loop or a string multiplication operation to print 'side' number of asterisks in a row. This will create a horizontal line of asterisks.

Completing the Function

Combine the loops so that for each iteration of the outer loop, a line of asterisks is printed; repeat this 'side' times for a complete square.

Key concepts

Function Definition

In C++, a function definition is a block of code designed to perform a specific task. It typically consists of a function header and a function body. The header includes the function's name, parameters, and return type:

• The function name should be descriptive of its task. For example, 'printSquare' could be a suitable name for our function that displays a square of asterisks.
• Parameters are the inputs required by the function to operate. In this exercise, we define a single integer parameter 'side', which will determine the dimensions of the square.
• The return type specifies what the function will output. Since our function only prints to the console and does not return any data, its return type should be 'void'.

The body of the function contains all the operations it will perform, enclosed in curly braces "{}".

For Loop

A 'for loop' is a control structure used in C++ to repeat a block of code a specific number of times. It is particularly useful when the number of iterations is known beforehand.

• A typical 'for loop' consists of three parts: initialization, condition, and increment.
• Initialization assigns a starting value to a counter variable.
• The condition evaluates whether the loop should continue running or stop.
• Increment updates the counter at the end of each loop iteration.

In our case, two 'for loops' are used: one to iterate over the rows (outer loop) and another to iterate over the columns (inner loop). This allows the function to draw each row of asterisks individually.

Parameter Passing

Parameter passing refers to how arguments are provided to a function when it is called. In C++, parameters can be passed by value, by reference, or via pointers.

• Passing by value means the function receives a copy of the actual input data, which is the simplest and safest method for small or primitive data types.
• Passing by reference allows the function to modify the original data, which is efficient for large data types.
• Pointers are a more complex method, offering flexibility but requiring careful handling to avoid errors.

For our 'printSquare' function, passing the 'side' parameter by value is suitable since we're only using it to control the loop iterations without modifying its value inside the function.

Loop Iteration

Loop iteration is the repetitive execution of a block of code within a loop. In the context of our task, we perform several iterations:

• The outer 'for loop' iterates through each row of the asterisk square, so it runs 'side' number of times.
• The inner loop (or a simple string multiplication) depends on how we choose to implement the row creation. It generates each line by iterating or repeating 'side' times as well.

This iteration creates the visual effect of a square by layering rows of asterisks on top of each other. By nesting the loops, each iteration of the outer loop corresponds to one complete row printed, ensuring a full square formation by the function's end.