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A global variable or static variable can be declared (or a symbol defined in assembly) with a keyword qualifier such as const, constant, or final, meaning that its value will be set at compile time and should not be changeable at runtime. Compilers generally put static constants in the text section of an object file along with the code itself ...
because the argument to f must be a variable integer, but i is a constant integer. This matching is a form of program correctness, and is known as const-correctness.This allows a form of programming by contract, where functions specify as part of their type signature whether they modify their arguments or not, and whether their return value is modifiable or not.
However, Java initially left open the possibility of implementing const, noticeable in that const is a reserved word, though it is not actually used as a keyword. Instead, Java has the object-oriented keyword final, which is used to qualify attributes (and thence also for local variables) as constant, but not to qualify types.
The equivalent keyword for variables is readonly [12] Note that a key difference between the C/C++ derived keyword const and the C# keyword readonly is that const is evaluated at compile time, while readonly is evaluated at runtime, and thus can have an expression that is only calculated and fixed later (at runtime).
By default, the value of boolean primitive type is false. This keyword is also used to declare that a method returns a value of the primitive type boolean. break Used to end the execution in the current loop body. Used to break out of a switch block. byte The byte keyword is used to declare a field that can hold an 8-bit signed two's complement ...
The difference between const and immutable is what they apply to: const is a property of the variable: ... The keyword final (detailed article) ...
The readonly keyword does a similar thing to fields. Like fields marked as const they cannot change once initialized. The difference is that one can choose to initialize them in a constructor, or to a value that is not known until run-time. [12] This only works on fields. readonly fields can either be members of an instance or static class members.
The final keyword is similar to the const keyword in C++, but its usage is more limited. [9] For the most part, const-correctness must rely on the semantics of the class' interface, i.e., it is not strongly enforced, except for public data members that are labeled final.