Use a typedef to define a new name for an existing type. For example,
typedef unsigned int size_t;allows you to use size_t as a name for type unsigned int, and
typedef char* charptr;says that charptr means the same thing as char*. Then
charptr p,q;makes both p and q have type charptr.
Array types
You can create a new name for an array type.
Type definition
typedef int Info[100];indicates that a value of type Info is an array of 100 ints. Then Info x;has the same effect as int x[100];and Info* p = new Info;has the same effect as int* p = new int[100]; Notice the similarity in structure between typedef char Line[80];and char line[80];A typedef is intended to look like a variable creation statement, but with a type substituted for the variable. |
Function types
A function has a type, and you can use typedef
to give a function type a name. Use a form that
looks a lot like a prototype for a function, but
start it with typedef and replace the function
name with the function type in parentheses. For example.
typedef int (Blue)(int,int);defines type Blue to be the type of a function that takes a pair of ints and returns an int. |
An enumerated type is a type with a small number of values. Define one using enum. For example,
enum Color {red, green, blue};defines a new type, Color, with three values called red, green and blue. Now
Color c = red;creates a variable c of type Color and initializes it to red.
Values of enumerated types are represented as nonnegative integers. The values are numbered in the order that you write them, starting at 0. For example, after the definition of type Color above, red is 0, green is 1 and blue is 2.
You can list as many members of an enumerated type as you like.
Define an enumerated type called Temperature that has three values, cold, mild and hot. Answer
Write a C++ directive to define ValueType to be the same as double. Answer