C++ Expressions and Enumeration Types

Boolean Operators and Readability

• The ! operator in C++ can reduce clarity in expressions and may create confusion.
• Before using the ! operator, consider if the expression can be made clearer without it.

Enumeration Types

• Enumeration types in C++ are defined by a list of integer constants, enhancing code clarity and readability.
• Example:
  • enum MonthLength{JAN_LENGTH = 31, FEB_LENGTH = 28, MAR_LENGTH = 31, … DEC_LENGTH = 31};

Default Enum Values

• If specific numeric values for enumerators are not set, C++ assigns consecutive values starting from 0.
• For instance:
  • enum Direction { NORTH = 0, SOUTH = 1, EAST = 2, WEST = 3}; is equivalent to enum Direction {NORTH, SOUTH, EAST, WEST};

Enumeration Value Assignment

• By default, the value of each enumeration constant is one more than its predecessor.
• Example:
  • For enum MyEnum{ONE = 17, TWO, THREE, FOUR = -3, FIVE};, the resultant values are: ONE = 17, TWO = 18, THREE = 19, FOUR = -3, FIVE = -2.

Strong Enums (enum classes)

• Introduced in C++11, strong enums (or enum classes) solve issues inherent to traditional enumerations.
• They do not behave like integers and will not conflict with global enum values.
• Strong enums are defined as follows:
  • Example: enum class Days { Mon, Tue, Wed };

Utilizing Strong Enums

• Strong enums require a qualifier to access their enumerators.
• Example:
  • Days d = Days::Tue;
  • Weather w = Weather::Sun;
• Variables d and w are not treated as integers, ensuring type safety.

Multiway Branches and Control Flow

• Multiway branches allow the selection of one action from multiple alternatives.
• The if-else statement serves as a branching mechanism and can contain nested if-else statements.
• This supports complex decision-making in program flow.