Chapter Summary

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A C structure provides the means to store several data items, usually of different types, in the same data object. You can use a tag to identify a specific structure template and to declare variables of that type. The membership dot operator ( . ) enables you to access the individual members of a structure by using labels from the structure template.

If you have a pointer to a structure, you can use the pointer and the indirect membership operator ( -> ) instead of a name and the dot operator to access individual members. To find the address of a structure, use the & operator. Unlike arrays, the name of a structure does not serve as the address of the structure.

Traditionally, structure- related functions have used pointers to structures as arguments. Modern C, including ANSI C, permits structures to be passed as arguments, used as return values, and assigned to structures of the same type.

Unions use the same syntax as structures. However, with unions, the members share a common storage space. Instead of storing several data types simultaneously in the manner of a structure, the union stores a single data item type from a list of choices. That is, a structure can hold, say, an int and a double and a char , and the corresponding union can hold an int or a double or a char .

The typedef facility enables you to establish aliases or shorthand representations of standard C types.

The name of a function yields the address of that function. Such addresses can be passed as arguments to functions, which then use the pointed-to function.

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