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Take a look at how printing hello world in Java is different from in python. Click The Code to edit it
Java
Python
As you can see, it takes a bit more code to print "Hello World" in Java. But why?
Hello world Breakdown
Hello world Breakdown
What you may notice at first is that stuff surrounding it you don't exactly understand
Java
Don't Worry About that right now, we will discuss that stuff another day.
The Part you probably do understand is the System.out.println("Hello World");
Java
It has that print thingy! very similar to the one in Python
Python
But Wait! Why does it say println in Java,
but print in Python????
Thats a good question
In Python the print() function:
prints the specified message
Then it moves the cursor to the next line
Let's look at an example
Code:
Python
Output:
In Java the print() function {
prints the specified message
}
I Wonder What Would Happen If I ran this Code...
Now you know
Now you know
{
{
In Java, System.out.print(); prints what's inside the ()
In Java, System.out.println(); prints what's inside the () and then moves the cursor down to the next line
}
}
The { }
The { }
These are called, "Curly Braces"
They are used to structure code.
Lets see an example code segment
Java
In this Code segment, if 1 were to equal 1 (it does) {
it would print, "Hello World"
}
As long as the println() statement is inside the Curly Braces it would print "Hello World" if 1=1 (it does)
Hey, this is similar to python. But in Python instead of curly braces ( { } ), we used Colons ( : )
Java
Python
Java Fun Fact {
Java Fun Fact {
Indentation is NOT required in Java.
Meaning all of the following would work (In Java not Python)
Java
Now you know {
Now you know {
How to structure code using curly braces
}
}
Variables
Variables
Variables are containers that hold data values
__________________________________________________________________________________________________________________________________________
These are the data Types:
String
Text, such as "Hello World", or "I would like to eat a banana"
Integer
Integers (Positive and negative numbers without decimoles) Such as 6 or -7
Boolean
True or False, such as true or false
Float and Double
Numbers with decimoles, such as 4.5, or 8.7 (Floats can hold up to 7 decimole digits and Doubles can hold up to 15-16)
Character
Characters (1 letter, 1 number, or 1 symbol), such as 'T' or '?'
__________________________________________________________________________________________________________________________________________
Java
To use a variable you must declare it
Declare it like this:
Java
Pro Tip: Variable names must follow these rules
(I hope that website is not blocked)
Let's see it in some code
Java
In This Code Segment,
a variable is declared, it is a String, it's called name, and is set to "John"
It then prints the variable, name
You can do operations with, and while declaring variables. See more operators
Java
In This Code Segment,
a variable is declared, it is an Integer, it's called x, and is set to 6*7 (* is a multiplication symbol) (6 x 7 = 42)
It then prints x - 1, x is 42 and 42 - 1 = 41, so it prints 41
Comparisons. see more comparisons
Java
In This Code Segment
x is set to 5 and y is set to 3
It then prints if x (5) is greater than y (3)
it is, so it prints true
Key Info
Key Info
Remember to end statements with a semicolon ( ; )
statements are executed, one by one, in the same order as they are written
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