Question

Rewrite the following expressions using the conditional operator. (Assume that all variables are declared properly.) a. if \((x>=y)\) \\[ z=x-y i \\] else \\[ z=y-x \\] b. if (hours \(>=40.0)\) \\[ \text { wages }=40 * 7.50+1.5 * 7.5 * \text { (hours }-40) \\] else wages \(=\) hours \(\star 7.50\) c. if (score > = 60) \(\operatorname{str}=\) "Pass" else \(\operatorname{str}=\) "Fail"

Short answer

a. \(z = (x >= y) ? (x - y) : (y - x)\) b. \(wages = (hours >= 40.0) ? (40 \times 7.50 + 1.5 \times 7.5 \times (hours - 40)) : (hours \times 7.50)\) c. \(str = (score >= 60) ? "Pass" : "Fail"\)

Step-by-step solution

Rewrite Expression (a)

To convert the if-else statement into a conditional operator, use the syntax `condition ? expression_if_true : expression_if_false`. For the expression provided:- Condition: `x >= y`- Expression if true: `z = x - y`- Expression if false: `z = y - x`Using the conditional operator, the expression becomes:\[z = (x >= y) ? (x - y) : (y - x)\]

Rewrite Expression (b)

Apply the conditional operator similarly as in Step 1. Identify the elements:- Condition: `hours >= 40.0`- Expression if true: `wages = 40 * 7.50 + 1.5 * 7.5 * (hours - 40)`- Expression if false: `wages = hours * 7.50`Using the conditional operator, rewrite:\[wages = (hours >= 40.0) ? (40 * 7.50 + 1.5 * 7.5 * (hours - 40)) : (hours * 7.50)\]

Rewrite Expression (c)

For the final expression rewrite using the conditional operator:- Condition: `score >= 60`- Expression if true: `str = "Pass"`- Expression if false: `str = "Fail"`Use the conditional operator to rewrite the expression:\[str = (score >= 60) ? "Pass" : "Fail"\]

Key concepts

Conditional Statements

Conditional statements in C++ allow the program to make decisions based on certain conditions. These conditions are usually determined by comparing variables or expressions. If the condition evaluates to true, the program will execute a specific block of code. Otherwise, it will execute another block. The most common conditional statement in C++ is the `if-else` statement.

The `if-else` statement works by checking if a condition is true and executing the corresponding code. For instance:

• If condition: the code will execute only if the condition is true.
• Else condition: the code will execute if the initial if condition is false.

In situations needing decisions, `if-else` statements make programs dynamic. They allow for different outcomes based on user input or system state.

Ternary Operator

The ternary operator is a shorthand way of writing simple `if-else` statements in C++. This operator, also known as the conditional operator, is represented by the syntax `condition ? expression_if_true : expression_if_false`. It allows evaluating a condition and returns one of two values, based on whether the condition is true or false.

This is how you can think of using the ternary operator:

• Condition: The expression which is evaluated for true or false. For example, `x >= y` in our exercise.
• Expression if true: The result returned if the condition is true.
• Expression if false: The result returned if the condition is false.

For our rewritten expressions: - If `x` is greater than or equal to `y`, `z` will be `x - y`; otherwise, `z` will be `y - x`.
The ternary operator can make code more concise, but overuse may lead to reduced readability, especially with complex conditions.

C++ Expressions

In C++, expressions are combinations of variables, operators, and values that produce a value. They are fundamental units that a program evaluates to execute its logic. Expressions can vary from simple arithmetic calculations to complex logical conditions.

Examples of these include:

• Arithmetic expressions: These include `x - y` or `hours * 7.50`, employing arithmetic operators like addition, subtraction, multiplication, etc.
• Logical expressions: These evaluate logical conditions, such as `x >= y`. They are often used in conditional statements to determine which branch of code to execute.

In our solutions, each expression is carefully constructed to evaluate whether certain conditions are met and perform actions like assignments accordingly. Efficient expression writing is crucial to a robust and logical execution flow in programming.