hhh hhh - 1 year ago 61
Java Question

Java: define terms initialization, declaration and assignment

I find the defs circular, the subjects are defined by their verbs but the verbs are undefined! So how do you define them?

The Circular Definitions

initialization: to initialize a variable. It can be done at the time of

assignment: to assign value to a variable. It can be done anywhere, only once with the final-identifier.

declaration: to declare value to a variable.

[update, trying to understand the topic with lambda calc]

D(x type) = (λx.x is declared with type)
A(y D(x type)) = (λy.y is assigned to D(x type))

%Then after some beta reductions we get initialization.
D(x type) me human // "me" declared with type "human"
A(y (D(x type) me human)) asking // "asking" assigned to the last declaration

%if the last two statemets are valid, an initialization exists. Right?

Answer Source

assignment: throwing away the old value of a variable and replacing it with a new one

initialization: it's a special kind of assignment: the first. Before initialization objects have null value and primitive types have default values such as 0 or false. Can be done in conjunction with declaration.

declaration: a declaration states the type of a variable, along with its name. A variable can be declared only once. It is used by the compiler to help programmers avoid mistakes such as assigning string values to integer variables. Before reading or assigning a variable, that variable must have been declared.