How does a 'while loop' differ from a 'for loop'?

A 'while loop' is designed to repeatedly execute a block of code as long as a specified condition remains true. This characteristic allows for dynamic looping where the number of iterations is not predetermined; instead, it depends on runtime evaluations of the condition. If the condition evaluates to false at any point, the loop terminates, making it particularly useful when the exact number of iterations is unknown beforehand.

This is in contrast to a 'for loop,' which typically involves a known number of iterations defined at the start, including initialization, a condition, and an increment/decrement step. While both loops can accomplish similar tasks, the 'while loop' provides greater flexibility for situations where the iteration count is contingent on changing conditions within the execution of the program.

The other options do not accurately describe the behavior of 'while loops.' They may reference aspects of loop structures, but they do not capture the essence of how 'while loops' fundamentally operate within programming logic.