Question

Correct the following code so that it prints the correct message: if (score > = 60) cout \(<<\) "You pass." \(<<\) endl else; cout \(<<\) "You fail." \(<<\) endl

Short answer

Correct the spacing, remove the unnecessary semicolon, and use curly braces around `cout` statements.

Step-by-step solution

Identify the issue

The given code has several syntax issues: unnecessary spacing around the comparison operator, a misplaced semicolon after `else`, and a missing pair of curly braces which may lead to logic errors.

Correct the spacing

Remove the space between the comparison operator `>` and the equal sign `=` so that it reads as `>=`. The correct line should be `if (score >= 60)`.

Remove unnecessary semicolon

The semicolon after `else` terminates the `else` block prematurely. Remove this semicolon to properly bind the `else` statement to its corresponding block.

Add curly braces

While optional in cases with only one statement, it's a good practice to use curly braces `{}` to clearly define the `if` and `else` blocks. After the `if` condition and `else` statement, include curly braces around the corresponding `cout` statements for clarity and maintainability of the code. The corrected block should be: ``` if (score >= 60) { cout << "You pass." << endl; } else { cout << "You fail." << endl; } ```

Key concepts

The Basics of If-Else Statements

An `if-else statement` is a fundamental concept in C++ programming that helps control the flow of the program. It allows the program to make decisions based on conditions. The `if` statement checks a given condition:

• If the condition is true, the code block inside the `if` statement executes.
• If the condition is false, the code block inside the `else` part executes, if it is provided.

Using `if-else` statements allows your program to perform different actions depending on changing variables. They are crucial for decision-making in programming and serve as a basic mechanism for branching logic.
Understanding how to accurately set up an `if-else statement` is important for ensuring your program behaves as expected.

Understanding Comparison Operators

Comparison operators in C++ are used to compare two values. They return a Boolean `true` or `false`, which is essential in conditions for `if` or `else` statements. Here are common comparison operators used in C++:

• `==`: Equal to
• `!=`: Not equal to
• `>`: Greater than
• `<`: Less than
• `>=`: Greater than or equal to
• `<=`: Less than or equal to

In the provided code snippet, the operator `>=` is used to determine if the variable `score` is greater than or equal to 60. Without the correct comparison operator, like in the original code where spacing led to an error, the condition evaluation can fail, leading to unintended behavior in your program.

Common Syntax Errors in C++

Syntax errors are mistakes in the sequence of characters or tokens that are intended to be a command. They prevent your program from compiling and running successfully in C++. When writing code, common syntax errors include:

• Incorrect placement of punctuation such as semicolons or braces.
• Mismatched pairing of parentheses or braces.
• Misusing operators by including inappropriate spaces.

In the original exercise, a few syntax errors were present including an extra space in the comparison operator, and a stray semicolon after the `else` which inadvertently terminated the `else` statement. Correcting these is essential for code to compile and function as intended.

Tips for Improving Code Maintainability

Code maintainability refers to how easily a software can be understood, corrected, adapted, and enhanced. Adhering to best practices in writing C++ code can greatly improve its maintainability. Here are some tips:

• Use consistent naming conventions to make variables and functions meaningful and descriptive.
• Include comments to explain the logic, particularly for complex sections.
• Organize code effectively using indentation and spacing for clarity.
• Utilize curly braces even for single-line `if`-`else` blocks to prevent errors when additional lines are added later on.

Improving maintainability not only helps your own understanding of the code in the future but also makes it easier for others who may need to work on it.