清华大学ACM集训队培训资料

所有的C++程序都是有函数组成的， 函数又叫做子程序，且每个C++程序必须包含一个main函数，编译器（能够把源代码转换成目标代码的程序）把翻译后的目标代码和一些启动代码组合起来，生成可执行文件，main函数就是可执行文件的入口，所以，每个C++程序有且只有一个main函数。-Tsinghua university ACM team training materials

All c++ program consists of function, the function is called subroutines, and each c++ program must contain a main function, the compiler (program) to translate source code into object code after the translation of the target code and some startup code, generate an executable file, the main function is the entry of the executable file, so that every c++ program one and only one main function.