The meaning of const in c++

const is used in C to declare constants to ensure that the variable value does not change during the execution of the program. The specific usage is as follows: add const before the variable type to declare a constant, such as: const int my_constant = 10; const can be used for basic types or user-defined types; the scope of a constant declared by const is in the block where it is declared; const can be used with references , to create a reference to a constant; const can be used with a pointer to create a pointer to a constant, but the pointer itself can be modified; const can be used to declare a constant object, neither itself nor its members can be modified.

The meaning of const in C

const is a keyword in C, used to declare constants. A constant is a special type of variable whose value cannot be modified during program execution.

Usage of const

To declare a constant, just add the const keyword before the variable type, as follows:

<code class="cpp">const int my_constant = 10;</code>

Declaration After a constant, the compiler prevents assignment to it. The compiler will generate an error if you try to modify the constant. Types of

const

const can be used with any data type, including basic types (such as int, float, etc.) and user-defined types (such as classes, structures, etc.) ).

Scope of const

const Constants declared are valid within the block in which they are declared. Therefore, constants declared outside a function or class are global constants, while constants declared inside a function or class are local constants.

const Reference

The const keyword can also be used with reference to create a reference to a constant. A reference is an alias that points to another variable. However, a const reference is a reference to a constant, which means that the variable pointed to by the reference cannot be modified.

const Pointers The

const keyword can also be used with pointers to create pointers to constants. Similar to a const reference, a const pointer is a pointer to a constant, which means that the variable pointed to by the pointer cannot be modified. However, the const pointer itself can be modified, which means it can point to a different constant.

const object

The const keyword can also be used to declare constant objects. Constant objects are objects that cannot be modified. This means that neither the object itself nor its members can be modified.

In short, const is a keyword used to declare constants, which forces the variables to remain unchanged during the execution of the program. const can be used with any data type as well as references and pointers, and its scope is limited by the block in which it is declared.

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