Java: What is a variable
Imagine the task, we need to print the phrase Father! On the screen twice or even five times. This problem can be solved in the forehead:
System.out.print("Father!");
System.out.print("Father!");
In the simplest case, this is what you should do, but if the phrase Father! Begins to be used more often, and even in different parts of the program, you will have to repeat it everywhere. Problems with this approach will begin when you need to change our phrase, and this happens quite often. We will have to find all the places where the phrase Father! Was used and perform the necessary replacement. And you can do differently. Instead of copying our expression, just create a variable with this phrase.
//greeting - translated as greeting
var greeting = "Father!";
System.out.print(greeting);
System.out.print(greeting);
In the var greeting = "Father!" - the value of "Father!" is assigned to a variable of type String named greeting.
When the variable is created, you can start using it. It is substituted in those places where our phrase used to stand. During code execution, the line System.out.print(greeting) replaces the variable with its contents, and then the code is executed. As a result, the output of our program will be as follows:
Father! Father!
https://replit.com/@hexlet/java-basics-variables-1
For the name of the variable, any set of valid characters is used, which include letters of the English alphabet, numbers and the characters -, _. In this case, the number can not be put at the beginning. Variable names are case-sensitive, that is, the name hello and the name heLLo are two different names, and therefore two variables.
The number of variables created is not limited in any way; large programs contain tens and hundreds of thousands of variable names:
var greeting1 = "Father!";
System.out.print(greeting1);
System.out.print(greeting1);
var greeting2 = "Mother!";
System.out.print(greeting2);
System.out.print(greeting2);
For the convenience of program analysis, it is customary to create variables as close as possible to the place where they are used.
Instructions
Create a variable with the name motto and the contents of What is Dead May Never Die!. Print the contents of the variable.
The exercise doesn't pass checking. What to do? 😶
If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:
- Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨
Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.
My code is different from the teacher's one 🤔
It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.
In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.
I've read the lessons but nothing is clear 🙄
It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.
By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.