C++ Programming: Enumeration Types and Strings, Slides of Computer Science

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Lecture

Enum, Arrays, Strings, Struct and more

Dr. Mageda Sharafeddin

Objectives In this chapter, you will:

• Learn how to create and manipulate your own simple data type—called the enumeration type
• Become aware of the typedef statement
• Explore the string data type, and learn how to use the various string functions to manipulate strings
• Learn about records (structs)
• Examine various operations on a struct
• Manipulate data using a struct
• Learn about the relationship between a struct and functions
• Examine the difference between arrays and structs C++ Programming: From Problem Analysis to Program Design, Seventh Edition 2

C++ Programming: Program Design Including Data Structures, Second Edition 4 Enumeration Type

• Data type - a set of values together with a set of operations on those values
• To define a new simple data type, called enumeration type, we need three things: - A name for the data type - A set of values for the data type - A set of operations on the values

C++ Programming: Program Design Including Data Structures, Second Edition 5 Enumeration Type (continued)

• A new simple data type can be defined by specifying its name and the values, but not the operations
• The values must be identifiers

C++ Programming: Program Design Including Data Structures, Second Edition 7 Examples

• The following are illegal enumeration types because none of the values is an identifier: enum grades{'A', 'B', 'C', 'D', 'F'}; enum places{1st, 2nd, 3rd, 4th};
• The following are legal enumeration types: enum grades{A, B, C, D, F}; enum places{first, second, third, fourth};

C++ Programming: Program Design Including Data Structures, Second Edition 8 Declaring Variables

• The syntax for declaring variables is: dataType identifier, identifier,...;
• The following statement defines an enumeration type sports enum sports{basketball, football, hockey, baseball, soccer, volleyball};
• The following statement declares variables of the type sports. sports popularSport, mySport;

10 Operations

• No arithmetic operation is allowed on enumeration types
• The following statements are illegal; mySport = popularSport + 2; //illegal popularSport = football + soccer; //illegal popularSport = popularSport * 2; // illegal

C++ Programming: Program Design Including Data Structures, Second Edition 11 Operations (continued)

• The increment and decrement operations are not allowed on enumeration types
• The following statements are illegal; popularSport++; //illegal popularSport--; //illegal

Examples of legal enum operations enum sports {BASKETBALL, FOOTBALL, HOCKEY, BASEBALL, SOCCER, VOLLEYBALL}; sports popularSport, mySport; popularSport = FOOTBALL; popularSport = static_cast(popularSport + 1); What is the value of popularSport after the last statement is executed? C++ Programming: Program Design Including Data Structures, Second Edition 13

Examples of legal enum operations enum sports {BASKETBALL, FOOTBALL, HOCKEY, BASEBALL, SOCCER, VOLLEYBALL}; FOOTBALL <= SOCCER HOCKEY > BASKETBALL BASEBALL < FOOTBALL for (mySport = BASKETBALL; mySport <= SOCCER; mySport = static_cast(mySport + 1))

-. -. -. C++ Programming: Program Design Including Data Structures, Second Edition 14

C++ Programming: Program Design Including Data Structures, Second Edition 16 Functions and Enumeration Types

• Enumeration type can be passed as parameters to functions either by value or by reference
• A function can return a value of the enumeration type

Enumeration as input or output

• enum courses {ALGEBRA, BASIC, PASCAL, CPP, PHILOSOPHY, ANALYSIS, CHEMISTRY, HISTORY};
• courses registered;
• char ch1, ch2;
• cin >> ch1 >> ch2; //Read two characters C++ Programming: Program Design Including Data Structures, Second Edition 17

C++ Programming: Program Design Including Data Structures, Second Edition 19 typedef Statement

• You can create synonyms or aliases to a previously defined data type by using the typedef statement
• The syntax of the typedef statement is: typedef existingTypeName newTypeName Ex: typedef int integer; integer i;

20 ANSI/ISO Standard C++, Namespaces namespace namespace_name { members } namespace globalType { const int N = 10; const double RATE = 7.50; int count = 0; void printResult(); } globalType::RATE; globalType::printResult();