In Java, all variables must be declared before they can be used. The basic form of a variable declaration is shown here:. Here are examples of how to declare variables of all the primitive data types in Java:. Here myByte, myShort, myChar, myInt, myLong, myFloat, myDouble all are variable name which have data type byte, short, char, int, long, float, double respectively. Here are examples of how to variables are initialize to all the primitive data types in Java:. Align multiple-line parameter lists with the first parameter.
Include a return type for every function. If a function does not return a value, use the keyword void as the return type. Use the keyword void in place of the parameter list if nothing is passed to the function. This is an example of a standard business function prototype:.
This is an example of a standard internal function prototype:. This is an example of a standard external business function definition:.
This is an example of a standard internal function definition:. Variables store information in memory that is used by the program. Variables can store strings of text and numbers. When you declare a variable, you should also initialize it. Two types of variable initialization exist: explicit and implicit. Variables are explicitly initialized if they are assigned a value in the declaration statement. Implicit initialization occurs when variables are assigned a value during processing. This information covers standards for declaring and initializing variables in business functions and includes an example of standard formats.
Declare all variables used within business functions and internal functions at the beginning of the function. Although C allows you to declare variables within compound statement blocks, this standard requires all variables used within a function to be declared at the beginning of the function block.
Declare only one variable per line, even if multiple variables of the same type exist. Indent each line three spaces and left align the data type of each declaration with all other variable declarations. Align the first character of each variable name variable name in the preceding format example with variable names in all other declarations. Use the naming conventions set forth in this guide.
When initializing variables, the initial value is optional depending on the data type of the variable. Generally, all variables should be explicitly initialized in their declaration. This is because constants are often located in program memory vs data memory, and their actual assignment is occurring at compile time vs run time. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow.
Learn more. Java: define terms initialization, declaration and assignment Ask Question. Asked 11 years, 7 months ago. Active 10 months ago. Viewed k times. The Circular Definitions initialization: to initialize a variable. Improve this question. Add a comment. Active Oldest Votes. Improve this answer. Silvio Donnini. Initialization is a change from a starting value.
Declaration is labeling with name and type. Assignment is a more general change in value, initialization a special type of assignment. Initialization is special just because it's the first assignment of a variable — Silvio Donnini. I don't think that primitives hold 0 or false values pre-initialization, given that fact that when you try to print an uninitialized variable, it produces a compile time error saying that the variable might not have been initialized, rather than printing their value.
In Java, fields of an object are automatically initialized to "empty" values null, zero, or false if there is no explicit initializer clause. But local variables in a block of code are not automatically initialized, and any attempt to read the value of a local without writing a value to it first will result in a compile-time error. For more information, see chapter 16 of the Java Language Specification. Assignment is simply the storing of a value to a variable. Initialization is the assignment of a value to a variable at the time of declaration.
These definitions also applies to fields. So basically "initialization" has two possible definitions, depending on context: In its narrowest form, it's when an assignment is comboed with declaration.
It allows, among other things, special array shorthand initializer syntax More generally, it's when an assignment is first made to a variable.
It allows, among other things, assignments to a final variable at multiple places. The compiler would do its best to ensure that exactly one of those assignments can happen, thus "initializing" the final variable There's also JVM-context class and instance initialization, OOP-context object initialization, etc.
It implies an initialization.
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