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This article mainly introduces "what will happen before and after the implementation of C++ 's main function". In daily operation, I believe many people have doubts about what will happen before and after the implementation of C++ 's main function. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts about "what will happen before and after the implementation of C++ 's main function". Next, please follow the editor to study!

Problem description

Whether or not all actions are caused by the main () function during the execution of the Cracket + language, take a look at the following code:

# include class A {public: a () {printf ("This is Constructor\ n");} ~ A () {printf ("This is destructor\ n");}}; Aaintint main () {printf ("This is main\ n");}

This code is simple, but in the end, it just prints the sentence This is main. Obviously not, the actual result is three sentences in the following order:

Analysis of This is ConstructorThis is mainThis is destructor problem

First of all, the main () function simply provides a function entry, and before the display code in the main () function executes, the compiler generates the _ main function, where all global objects are constructed and initialized. In a nutshell, the allocation of static variables, global variables, and global objects is done long before the main () function, so not all actions in CAccord Cleavage + are caused by the main () function.

Similarly, after the main () function is executed, the program exits, and the global variables and global objects are destroyed, so the corresponding code is executed in the main () function.

In the above example, the constructor of an executes first, then the main, and finally the destructor of a.

At this point, the study of "what happens before and after the execution of C++ 's main function" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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