Question

Write an \(1 \mathrm{f}\) -else statement that assigns 20 to the variable \(y\) if the variable \(x\) is greater than \(100 .\) Otherwise, it should assign 0 to the variable \(y\)

Short answer

```python if x > 100: y = 20 else: y = 0 ``` A) Assign 100 to the variable y if x is greater than 20. B) Assign 20 to the variable y if x is greater than 100; otherwise, assign 0 to y. C) Assign 0 to the variable y if x is greater than 100; otherwise, assign 20 to y.

Step-by-step solution

Write the if statement condition

First, we need to write the condition for our if statement. In this case, the condition is: (x > 100). If this condition is true, we will assign 20 to the variable 'y'. The code for this in Python will look like this: ```python if x > 100: ```

Write the code to execute if the condition is true

Next, we need to write the code that will be executed if the condition from step 1 is true. In this case, we want to assign 20 to the variable 'y'. The code for this in Python will look like this: ```python if x > 100: y = 20 ```

Write the else statement

Now, we need to write the else statement, which is the code that will be executed if the condition from Step 1 is false. In this case, we want to assign 0 to the variable 'y'. The code for this in Python will look like this: ```python if x > 100: y = 20 else: y = 0 ``` The final and complete if-else statement is as follows: ```python if x > 100: y = 20 else: y = 0 ``` This if-else statement will assign 20 to the variable 'y' if the variable 'x' is greater than 100. Otherwise, it will assign 0 to the variable 'y'.

Key concepts

Conditional Statements

Conditional statements are at the heart of decision-making in programming. They allow a program to choose different paths of execution based on certain conditions. This concept is similar to making decisions in real life, where the outcome is determined by various 'if this, then that' scenarios.

For instance, in the exercise provided, we use an if-else structure to decide what value to assign to a variable y based on the value of another variable x. If the condition (x > 100) is met, then y is set to 20. If the condition is not met, which means that x is less than or equal to 100, y is set to 0.

This structure is critical to understand as it affects the flow of control within the program. Further expanding on the example, you could introduce additional conditions using elif for more complex logic, like setting different values for y when x falls within specific ranges.

Programming Logic

Programming logic involves the sequences of instructions that tell the computer what to do. It's basically the reasoning part of programming, where a programmer sets out the rules that will dictate how the program will function.

In the context of the given problem, the logic is straightforward: check a variable's value and assign another variable based on that check. The simplicity of this logic can be deceptive, as more complex programs require intricate logical structures with multiple conditional statements and variables impacting one another.

To improve your logic skills, it's essential to practice with different types of problems. Try out scenarios where multiple conditions need to be checked, or where the logical flow requires you to think several steps ahead, much like in a game of chess. Ideally, the logic should be clear, concise, and as efficient as possible, to make the program easy to understand and maintain.

Variable Assignment

Variable assignment is a fundamental concept where a value is 'assigned' to a named variable. In programming, variables are like containers storing data that can be manipulated.

In our exercise, the variable y is assigned the value 20 if a condition is true, and 0 if the condition is false. The act of assignment is performed with the = operator, which should not be confused with the equality operator ==, used to compare values.

Understanding variable assignment is crucial because it enables you to store and update data dynamically. Think of variables as placeholders that can be changed and acted upon throughout the lifecycle of the program. To enhance understanding, play with different types of variables - such as integers, strings, and booleans - and practice assigning and reassigning different values to see how they affect the program's output.