Java - For loop

A very important concept in programming is looping. In this post we will take a look at the for loop in java. Let us say for example that we want to display some text 20 times. If we were to code that without a loop, we would have to write 20 statements, very tedious indeed. Here is how a for loop in java will help us out:

public class ForLoopExample {
 public static void main(String[] args){
  
  for (int index = 1; index <= 20; index++){
   System.out.println("I am so glad I didn't have to type this " + index + " times!");
  }    
 }

}

If you look at the actual for statement, you will notice a couple of things in the brackets. First we see the statement of int index = 1; what this does is declare an int variable to store a number as a counter of sorts, so the program knows how many times it has run through the loop. The second part index <= 20; tells the program to run the code until the index variable holds a value of 20. The third part index++ instructs java to increment the variable index by one every time the loop is run through.

Below is what the result is when you run the program:

I am so glad I didn't have to type this 1 times!
I am so glad I didn't have to type this 2 times!
I am so glad I didn't have to type this 3 times!
I am so glad I didn't have to type this 4 times!
I am so glad I didn't have to type this 5 times!
I am so glad I didn't have to type this 6 times!
I am so glad I didn't have to type this 7 times!
I am so glad I didn't have to type this 8 times!
I am so glad I didn't have to type this 9 times!
I am so glad I didn't have to type this 10 times!
I am so glad I didn't have to type this 11 times!
I am so glad I didn't have to type this 12 times!
I am so glad I didn't have to type this 13 times!
I am so glad I didn't have to type this 14 times!
I am so glad I didn't have to type this 15 times!
I am so glad I didn't have to type this 16 times!
I am so glad I didn't have to type this 17 times!
I am so glad I didn't have to type this 18 times!
I am so glad I didn't have to type this 19 times!
I am so glad I didn't have to type this 20 times!

Java - Hello world

The most common and basic lesson in programming is the "Hello World" tutorial. The purpose of this tutorial is to write the most basic program which displays the text "Hello World". Here is an example of this in Java:

public class HelloWorld {
 public static void main (String[] args){
  
  // Print "Hello World" to the console
  System.out.println("Hello World");
 }

}

In Java and other programming languages, all code is contained in either a class or multiple classes. The class in this example is HelloWorld. In Java the execution of the program begins in the main method. In order to make your code easier to understand, it is best practice to add comments to it. Comments in Java are preceded by // and aren't read by the compiler. If you have multiple lines of comments, use /* at the beginning and */ at the end.

The last line of code here displays the text between the brackets in the Java console. This is the simplest way to print out information in Java.