What does a while loop do in programming?

A while loop is a fundamental control structure in programming that allows a block of code to execute repeatedly, as long as a specified condition remains true. The defining feature of a while loop is its dependence on a condition; it first evaluates this condition before each iteration. If the condition evaluates to true, the code inside the loop is executed. Once the condition evaluates to false, the loop ceases to execute. This mechanism provides a flexible way to repeatedly perform operations as long as certain criteria are met, making it particularly useful for scenarios where the number of iterations is not known beforehand.

In contrast, the other options describe different types of loops or behaviors that do not align with the purpose of a while loop. For instance, a loop that executes a fixed number of times pertains more to a for loop, which is designed to iterate a specific number of times based on predetermined limits. A loop that runs only once is essentially a misunderstanding of looping structures, as any loop is inherently designed to repeat if its condition permits. Lastly, a loop that iterates over an array is typically associated with a for-each loop or other iterator patterns, focusing on traversing data structures rather than the condition-based evaluation found in while loops.