Summary of const type data

This section introduces const Type data and references , They can be used to protect shared data . The following is a summary of several const The usage and difference of type data , Suppose there is student class .

(1) studentconst stud; perhaps conststudent stud;

       Express stud It's a regular object , Its value cannot be changed under any circumstances .

(2) voidstudent::func() const

       Express func() The function is student Class , You can reference , however , Member variables in this class cannot be modified .

(3) student* const ps;

       Express ps It's a student Pointer to type , Is a constant pointer , therefore , The pointer cannot be modified ps Value . however , You can modify ps The pointer points to the data of the object .

(4) const student* ps;

       Express ps It's a student Pointer to type , It refers to a constant object . therefore , Cannot be modified ps Data pointing to the object . however , You can modify ps Pointer value .

(5) const student& stud = s;

       Express stud It's a reference , quote s object . And it often refers to objects . therefore , Cannot be modified stud Reference the data of the object .

8 summary

This chapter introduces C++ Data protection of class objects , This knowledge point reflects the “ encapsulation 、 Protect ” characteristic , An object can have private data , Data that can not be modified .

that ,C++ Provides const keyword , It can effectively protect the security of data . therefore , In the design of many functions , In order to protect the security of data , Can be defined as const type . Good at using const data type , It can effectively protect the security of data .

Readers should carefully analyze , Master every knowledge point , then , Summarize your understanding of this knowledge point . The knowledge summarized by myself , Understanding is profound , Is the knowledge you have mastered .

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