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A condition-controlled loop is a programming construct that repeatedly executes a block of code as long as a given condition is true. There are two main types of condition-controlled loops: while loops and do-while loops.

A while loop checks the condition before executing the code inside the loop. If the condition is true, the code inside the loop is executed. The loop continues to check the condition and execute the code, as long as the condition remains true. If the condition is initially false, the code inside the loop will not be executed at all. For example, in Python: ```python count = 0 while count < 5: print("Count:", count) count += 1 ``` This code initializes a variable 'count' to 0, and executes the loop as long as 'count' is less than 5, printing the value of 'count' and then incrementing it by 1.

A do-while loop is similar to a while loop, but the code inside the loop is executed at least once, even if the condition is initially false. This is because the condition is checked after executing the code inside the loop. Python does not have a built-in do-while loop, but it can be simulated using a while loop like this: ```python count = 5 while True: print("Count:", count) count += 1 if count > 5: break ``` This code initializes a variable 'count' to 5, and uses a 'while True' loop to execute the code inside the loop at least once. The loop will continue as long as the condition (count > 5) is true. In this case, the code inside the loop will be executed once, and then the loop will terminate.

Condition-controlled loops are used when the number of iterations is not known in advance, and the loop needs to continue until a specific condition is met. Examples include reading input from a user or a file, performing calculations until a particular accuracy is achieved, or waiting for an event to occur in event-driven programming.