Question

Identify the termination condition in each of the following iterative statements. a. while (Count \(<5\) ): b. repeat: until (Count \(==1\) ) c. while \(((\) Count \(<5)\) and \((\) Total \(<56))\) :

Short answer

a. Count >= 5; b. Count == 1; c. Count >= 5 or Total >= 56.

Step-by-step solution

Analyze Condition (a)

For the statement 'while (Count < 5)', the loop continues to execute as long as the condition 'Count < 5' is true. The termination condition is reached when 'Count' becomes 5 or greater, causing the loop to stop executing.

Analyze Condition (b)

For the statement 'repeat: until (Count == 1)', the loop will continue until the condition 'Count == 1' is true. This means the loop stops when 'Count' equals 1. Until this condition is met, the loop will keep iterating.

Analyze Condition (c)

For the statement 'while ((Count < 5) and (Total < 56))', the loop continues executing as long as both conditions 'Count < 5' and 'Total < 56' are true. The termination condition occurs when either 'Count' reaches 5 or more, or 'Total' reaches 56 or more, causing the loop to stop.

Key concepts

Iterative Statements

Iterative statements, often referred to as loops, are instructions or codes that repeat until a specific condition is met. They are a core component of many programming languages.

• Iterations can help automate repetitive tasks.
• They improve code efficiency by eliminating manual repetition.

Imagine needing to print "Hello" five times. Instead of writing print statements five times, you use a loop. This loop runs the print command, checks a condition, and only repeats if that condition hasn’t been met yet.
There are various types of loops, such as 'for' loops, 'while' loops, and 'repeat-until' loops, each used under different scenarios. Understanding the loop type to use can greatly enhance the structure and execution efficiency of your code.

While Loop

The 'while' loop is a type of iterative statement that repeats a section of code as long as a specified condition remains true.

• The condition gets tested before execution of loop body.
• If the condition is false right from the start, the loop may never execute.

This is particularly useful when you don’t know in advance how many times you need to iterate. For instance:
```python while (Count < 5): # code to execute ```
The code will keep executing as long as the Count variable is less than 5. When Count reaches 5, the loop stops. Properly managing the loop by including mechanisms that eventually cause the condition to become false is crucial to prevent infinite loops.

Repeat-Until Loop

The 'repeat-until' loop is another type of iterative statement used in programming. It works similarly to a while loop with one significant difference: the condition is tested after the loop body executes.

• This means the loop will always execute at least once.
• The loop continues until the condition is true.

For example:
```python repeat: # code to execute until (Count == 1) ```
This block of code executes once, checks whether Count is equal to 1, and if not, it repeats until Count becomes 1. The key advantage here is its guarantee of minimum one execution, useful in situations where execution should occur at least once.

Logical Conditions in Loops

Logical conditions play a critical role in ensuring loops function as intended. They determine when the loop will terminate. By using logical operators like AND, OR, and NOT, complex conditions can be crafted.

• AND: All connected conditions must be true for the overall expression to be true.
• OR: Only one of the connected conditions needs to be true for the overall expression to be true.
• NOT: Inverts the truth value of a condition.

Consider this example: `while ((Count < 5) and (Total < 56))`. Here, the loop continues only if both 'Count < 5' and 'Total < 56' are true. Once either condition is false, the loop stops.
Understanding logical operations allows for more nuanced and efficient loop control in programming. Encouraging students to practice working with these conditions and observe their effects is an effective way to grasp their utility.