C++程序设计课件_chapter10.pptVIP

* chapter 10 Simple Data Type: Built-In and User-Defined Goals To be able to identify all of the simple data types provided by the C++ language. To become familiar with specialized C++ operators and expression To be able to distinguish between external and internal representations of character data. To understand how floating-point numbers are represented in the computer. To understand how the limited numeric precision of the computer can affect calculations. To be able to select the most appropriate simple data type for a given variable. To be able to declare and use an enumeration type. To be able to use the For and Switch statements with user-defined enumeration types. To be able to distinguish a named user-defined type from an anonymous user-defined type. To be able to create a user-written head file. To understand the concepts of type promotion and type demotion. 10.1 Built-In Simple Types Data type : a specific set of data value (which we call the domain) along with a set of operations on those values. Simple (atomic )data type : A data type in which each value is atomic (indivisible) When we say that a value is atomic ,we mean that it has no component parts that can be accessed individually. For example, a single character of type char is atomic, but the string “Good Morning” is not (it is composed of 12 individual characters) . Another way of describing a simple type is to say that only one value can be associated with a variable. In contrast, a structured type is one in which an entire collection of values is associated with a single variable of that type. C++ data types simple float floating double long double integral char short int long bool enum address pointer reference structured array struct union unsigned enum is a mechanism with which we can define our own simple data types. The integral types char ,short,int , and long represent nothing more than integers of different size.Similarly , the floating-point types float,