What is the difference between a while loop and a for loop?

A while loop repeats a block of code until a condition is false, whereas a for loop repeats a block of code for a specific number of times.

In more detail, a while loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The while loop can be thought of as a repeating if statement. The code inside the loop is executed, over and over again, as long as the condition is true. Once the condition becomes false, the loop terminates. This makes while loops suitable for situations where you don't know how many times the loop should run, such as reading lines from a file until you reach the end.

On the other hand, a for loop is also a control flow statement that allows code to be executed repeatedly. However, a for loop is designed to simplify the process of writing loops that are executed a specific number of times. A for loop is characterised by three parts: the initialisation, the condition, and the iteration. The initialisation is executed once at the beginning of the loop, the condition is checked before each iteration of the loop, and the iteration is executed at the end of each loop iteration. This makes for loops ideal for situations where you know how many times the loop should run, such as iterating over elements in an array.

For those interested in deeper understanding, exploring standard algorithms often utilises these looping constructs to manage iterative processes effectively, which you can read more about here.

Additionally, programming constructs including loops are crucial in writing efficient code, as outlined in our notes on fundamental programming constructs.

Moreover, understanding how to define and use procedures effectively in programming involves leveraging these types of loops, which is further discussed here.

A-Level Computer Science Tutor Summary: In summary, a while loop runs code repeatedly as long as a certain condition is true, perfect for when you're unsure how many times you need the loop to run. A for loop, however, repeats code a specific number of times, with its structure making it easier to manage when you know the exact number of repetitions required.