Loops are used to run the same piece of code multiple times. The code in a loop runs repeatedly as long as a certain condition evaluates to
Let’s look at the example given below,
where we print the numbers from 1 to 5 using a
The steps followed while executing the above
for loop are as follows:
Step 1 - At the beginning of the loop, the first statement,
let i = 1 executes, which creates a variable
i and gives it a value of 1.
Step 2 - The loop then moves on to its first iteration. Here, the second statement,
i < 6 is checked to see if it evaluates to
true. Since the value of
i is currently 1, the second statement is indeed
true. The code block of the loop is then run.
Step 3 - The third statement,
i++ finally executes at the end of this iteration, when everything inside the code block has been executed. Here, we increment the value of
i by 1.
Step 4 - The loop then moves on to the next iteration, wherein it repeats the steps from Step 2.
Steps 2, 3 and 4 are repeated as long as the second statement evaluates to
true. At one point, the value of
i will be 6 at the beginning of an iteration, due to which the second statement,
i < 6 will evaluate to
false. At that point, the loop immediately terminates and no more code is run.