Identifier In CPP

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In C++, an identifier is a name given to various program elements such as variables, functions, classes, etc. Identifiers are used to uniquely identify these elements within the program.

Here's a more formal definition:

An identifier in C++ is a sequence of characters (letters, digits, and underscores) that serves as a name for various program elements, such as variables, functions, classes, etc.

In C++, identifiers follow certain rules:

They can consist of letters (both uppercase and lowercase), digits, and underscores.
The first character must be a letter or an underscore.
Identifiers are case-sensitive.
They cannot be keywords (reserved words) of the C++ language.
They cannot contain spaces or special characters (except underscores).

Examples of valid identifiers in C++:

myVariable
_count
calculateSum
ClassName
MAX_SIZE
daysOfWeek
my_function

Examples of invalid identifiers in C++:

2ndValue (starts with a digit)
class (reserved keyword)
my variable (contains space)
my-variable (contains special character)
sum# (contains special character)

An identifier is a sequence of characters used to indicate one of the following:

Variable Name :
```
int age;
float salary;
```

Function Name :

void greetUser()
{

}

int calculateSum(int a, int b)
{

}

Label Name :

startLoop:
    // loop code
    goto startLoop;

Constant names (often defined using const):
```
const int MAX_SIZE = 100;
```

Class Name :

class Student {
    // class members
};

structure Name :

struct StructureName {
    // Member declarations
};

union Name :

union UnionName {
    // Member declarations
};

Object Name :
```
Student s1;
```

Enum Type Name :

enum DaysOfWeek {
    Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday
};

Data Member of a class Name :

class MyClass {
public:
    int myNumber; // Declaration of a data member
};

Class-member Function Name :

class MyClass {
public:
    void myFunction(int x, int y); // Declaration of a member function
};

typedef Name :
```
typedef int Name;
Name myNumber = 5;
```
Macro Name :
```
#define SQUARE(x) ((x) * (x))
```

Macro parameter Name :

#define MACRO_NAME(parameter_name) // Macro definition

Namespace names:

namespace math {
// namespace contents
}

Template parameter names:

template 
class Container {
    // class members
};

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