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10.3: Typedef - An Alias

  • Page ID
    10298
  • General Discussion

    The typedef statement allows the programmer to create an alias, or synonym, for an existing data type. This can be useful in documenting a program. The C++ programming language syntax is:

    typedef <the real data type> <the alias identifier name>;

    Let's say a programmer is using a double data type to store the amount of money that is being used for various purposes in a program. He might define the variables as follows:

    Regular Definition of Variables
    double    income;
    double    rent;
    double    vacation;
    

    However, he might use the typedef statement and define the variables as follows:

    Using typedef when Defining Variables
    typedef double cash;
        the typedef must be defined before its use
    cash  income;
    cash  rent;
    cash  vacation;
    

    The typedef statement is not used very often by beginning programmers. It usually creates more confusion than needed, thus stick to using the normal data types at first.

    Definitions

    typedef
    Allows the programmer to create an alias, or synonym, for an existing data type.