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Naming Convention in C++

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  • Difficulty Level : Easy
  • Last Updated : 24 Jul, 2022

Naming a file or a variable is the first and the very basic step that a programmer takes to write clean codes, where naming has to be appropriate so that for any other programmer it acts as an easy way to read the code. In C++, naming conventions are the set of rules for choosing the valid name for a variable and function in a C++ program. 

  • The class name should be a noun.
  • Use upper case letters as word separators, lower case for the rest of the word in the class name.
  • The first character in the class name must be upper case.
  • No underscores (‘_’) are permitted in the class name.
  • The private attribute name in class should be prepended with the character ‘m’.
  • After prepending ‘m’, the same rules will be followed for the name like that for the class name.
  • Character ‘m’ also precedes other name modifiers also. For example, ‘p’ for pointers.
  • Each method/ function name should begin with a verb.
  • The first character of function/ method argument names should be lower case. All words starting after the first letter should be the upper case with class names.
  • The variable name should begin with an alphabet.
  • Digits may be used in the variable name but only after the alphabet.
  • No special symbols can be used in variable names except for the underscore(‘_’).
  • No keywords can be used for variable names.
  • Pointer variables should be prepended with ‘p’ and place the asterisk ‘*’ close to the variable name instead of pointer type.
  • Reference variables should be prepended with ‘r’. This helps to differentiate between the method returning a modifiable object and the same method returning a non-modifiable object.
  • Static variables should be prepended with ‘s’.
  • The global constants should be all capital letters separated with ‘_’.
  • No special character is allowed in the file name except for underscore (‘_’) and dash (‘-‘).
  • The file name should end with the .cc extension in the end or should end with the .cpp extension.
  • Do not use filenames that already exist in /user/include. or any predefined header file name.

Example:

Calculate the product of two variables-
Name variable 1 as var1
Name variable 2 as var2
Name result as product or pdt

This will be more convenient naming convention than assuming the random names like x, y, and z.

Advantages of Naming Conventions:

Following a set of rules in naming convention while writing the code helps in the following ways-

  1. Avoids naming conflicts.
  2. Improves clarity of the code in case of ambiguity.
  3. Helps to formalize and promote consistency within a team.
  4. Improves understanding and readability of the code.

Illustrations:

  1. Class: Name a class in C++ after what it is and use upper case letters as word separators. The class name should be a noun. For example, ReverseString, Multiply2Numbers. The name should be specific and hint at the functioning of the class without glancing at the body of the class. This type of conventions called PascalCase.
  2. Methods: Every method and function performs an action, so the function name should make it clear what it does. For example, writeDataToFile() is more convenient name than WriteFile(). Function names should begin with a verb. This type of conventions called camel case. We can also follow snake_case for methods. In snake case we have to join two separate words using ‘_’ (Underscore).
  3. Constants: Constants should be all capital letters with ‘_’ separators. For example, MAX_INT, TWO_PI, etc.

Naming Convention in C++

Names in the program are the key to program readability. If the name is appropriate in a program then everything fits together and relationships are clear, meaning is derivable. C++ uses CamelCase as a practice for writing names of methods, variables, classes, packages, and constants. 

CamelCase is a naming convention where a name is formed of multiple words that are joined together as a single word with the first letter of each of the word capitalized.

Below are the naming conventions of C++ programming. They must be followed while writing code in C++ for good maintenance, readability, understanding of the program.

Type 1: Classes and Class Attributes Names

  • The class name should be a noun.
  • Use upper case letters as word separators, lower case for the rest of the word.
  • The first character in the class name must be upper case.
  • No underscores (‘_’) are permitted in the class name.

class PerimeterRectangle

class FingerprintScanner

  • The private attribute name in class should be prepended with the character ‘m’.
  • After prepending ‘m’, the same rules will be followed for the name like that for the class name.
  • Character ‘m’ also precedes other name modifiers also. For example, ‘p’ for pointers.

class PerimeterRectangle
{
    public:
    int perimeter;
    private:
    int mLength;
    int mWidth;
}

Type 2: Functions and Function Argument Names

Usually, every function in C++ performs one or more actions, so the name of the function should clearly hint what it does. Each method/ function name should begin with a verb.

  • Suffixes are sometimes useful. For example,
    • Count- the current count of the counter.
    • Key- the key value.
  • Prefixes are sometimes useful. For example,
    • get-get value.
    • set- set value.

 The same name convention is used as that for the class names.

int getValue();

int SolveEquation();

The first character of function/ method argument names should be lower case. All words starting after the first letter should be the upper case with class names.

int PerimeterRectangle(int lengthRectangle, int widthRectangle)

Type 3: Variables

When the variables are declared dynamically using the new keyword or if the variables are declared as class attributes then they take memory from the heap and when the variables are created in a C++ program, the memory is allocated from the program stack.

  • The variable name should begin with an alphabet.
  • Digits may be used but only after the alphabet.
  • No special symbols can be used in variable names except for the underscore(‘_’).
  • No keywords can be used for variable names.

int total_cost;

int length;

Pointer variables should be prepended with ‘p’ and place the asterisk ‘*’ close to the variable name instead of pointer type.

int *pName;

int *pAge, address; // Here only pAge is a pointer variable

Reference variables should be prepended with ‘r’. This helps to differentiate between the method returning a modifiable object and the same method returning a non-modifiable object.

Static variables should be prepended with ‘s’.

static int sCount;

Type 4: Constant

The global constants should be all capital letters separated with ‘_’.

const double TWO_PI = 6.28318531; 

Type 5: File Naming;

  • No special character is allowed in the file name except for underscore (‘_’) and dash (‘-‘).
  • The file name should end with the .cc extension in the end or should end with the .cpp extension.
  • Do not use filenames that already exist in /user/include. or any predefined header file name.

helloworld.c       // Valid

hello_world.cpp    // Valid

 hello-world.cpp   // Valid

hel-lo_world.cpp  // Valid

hello* world.cpp  // Not Valid

iostream.cpp // Not Valid

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