For Loop in Java: Explained with Examples

Let us now take a look at how you can do the same tasks of printing numbers from 1-100.

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Video Transcript

You learnt earlier how to print all the numbers between one to 10 using a while loop. Now, can we do the same task using a for loop? That is, print all the numbers between one to 100 using the for loop. For that I write the keyword for here. Then I initialize my variable NUM from one. Then I put a semicolon to indicate that my initialization is now complete. Then in the next step I say I tell the program till what point do I want this for loop to run? So basically I want this for loop to run till NUM is less than equal to 100. Then in the next step I tell what change should occur in NUM at each and every step. So I say NUM plus plus. Now here inside the for loop I'll simply print the value of NUM. So basically the basic syntax for running a for loop is that in the beginning you declare and initialize whichever variable you wish to change. Then you tell the for loop how many times you wish this for loop to execute. That is, you tell till what point does your variable need to go? In our case,

NUM will go till 100 including 100. And in the next step you would specify the for loop what change will occur in NUM at each and every step. So let us try to run this program and see if it works. So here you can see that on the console all the numbers between one to 100 get printed. Imagine that I would have forgotten to add is equal to sign here. Then what would have happened?

Here again, all numbers get printed from starting from one till 99. This is because again my NUM will go maximum till 99. And once my NUM becomes 99, it will check. It will increment that 99. In the next step that will my NUM will become 100. Then in the next step when I try to run my for loop, this particular condition will become false and hence this for loop will get broken.

Video Recap

• A for loop can be used to print numbers between one to 100

• Use "for" keyword and initialize variable NUM to one with a semicolon

• Set the loop to run until NUM is less than or equal to 100

• Specify the change that occurs in NUM at each step with "NUM++"

• Print the value of NUM inside the loop

• The basic syntax for a for loop is to declare and initialize the variable, set the loop limit, and specify the change in the variable at each step

• Without the "is equal to" sign, the loop will print numbers from one to 99 instead of 100

• When NUM becomes 100, the loop will break as the condition is no longer true.

As you saw, the same task of printing numbers sequentially is simpler using the for loop.

Let us take a look how you can do the task of calculating the product of numbers of 1 to 10 via the for you loop.

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Even the task of computing product of numbers from 1 till 10 is an easier task with a for loop.

Now consider a situation where every time the loop executed, you asked the user if you should print another number and printed a number every time a user entered yes until he/she entered no.

In such a case, a while loop will be a better choice where the loop will execute while userInput=”yes”.

In the next segment, you will learn about the third kind of loop called the do-while loop.