Introduction to For Loops

A for loop is a control flow statement, allowing code to be executed repeatedly.
These loops are typically used when the number of iterations is known beforehand.
The basic structure of a for loop includes initialisation, test condition, and increment/decrement.

For Loop Syntax

In a for loop, the initialisation usually involves setting a control variable to a start value.
The test condition checks if the loop should continue.
Increment/decrement changes the control variable’s value after each loop cycle. Commonly, this means increasing or decreasing by 1.

Control variables can be used within the loop to perform calculations or manipulate other variables.
Braces ({ and }) encapsulate what runs each iteration of the loop. If only one line follows the for statement, braces can be omitted.
It’s important to ensure the loop will end, preventing an infinite loop. This typically means designing the test condition and increment/decrement correctly.

Algorithms often require repeated actions, making for loops particularly useful.
Nested for loops allow for the execution of other loops within a single iteration of the main loop, often used for multi-dimensional arrays or complex counting tasks.
The break statement can be used to prematurely terminate the loop, usually based on a certain condition being met.
The continue statement can be used to skip one iteration of the loop, moving onto the next iteration.

A for-each loop (also known as an enhanced for loop) is used to traverse items in collections (like arrays or lists). It’s more concise but less flexible than a traditional for loop.
For loops can also iterate over characters in a string, or elements in a data structure.
Iterating over data structures or strings is fundamental to many algorithms, from sorting and searching, to data analysis and transformation.