In programming languages, iteration refers to the process of repeatedly executing a block of code until a specified condition is met.

Iteration is a core concept in computer programming and serves as a control flow mechanism. It enables a set of instructions, known as a block of code, to be executed multiple times. This repetition can occur for a predetermined number of times or continue until a certain condition evaluates to false. Typically, this condition is a logical expression that returns either true or false. If the condition is true, the loop persists; if false, the loop terminates, allowing the program to proceed to the next block of code.

There are several types of iteration structures in programming, including ‘for’ loops, ‘while’ loops, and ‘do-while’ loops. A ‘for’ loop is generally employed when the total number of iterations is known beforehand. It utilizes a counter that increments or decrements with each iteration, continuing until the counter reaches a defined value. In contrast, a ‘while’ loop continues to iterate as long as a specified condition remains true. The condition is evaluated before each iteration; if it is false, the loop is entirely skipped. A ‘do-while’ loop functions similarly to a ‘while’ loop but checks the condition after each iteration, guaranteeing that the loop executes at least once.

Iteration is an invaluable tool for programmers because it automates repetitive tasks, enhancing both the efficiency and readability of the code. For instance, if you wanted to print the numbers from $1$ to $10$, you could write ten separate print statements. Alternatively, you could use a ‘for’ loop to iterate through the range of numbers, printing each one sequentially. This latter method is not only more concise but also more adaptable, allowing for easy modifications to print any range of numbers.

In conclusion, grasping the concept of iteration is essential for anyone learning to program. It is a fundamental principle that supports various computing tasks, from processing large datasets to managing the flow of user interactions within a software application.