在实际开发中，有时候我们需要实现几个功能类似的函数，只是有些细节不同。例如希望交换两个变量的值，这两个变量有多种类型，可以是 int、float、char、bool 等，我们需要通过参数把变量的地址传入函数内部。在C语言中，程序员往往需要分别设计出三个不同名的函数，其函数原型与下面类似：(In actual development, sometimes we need to implement several similar functions, but there are some details. For example, we want to exchange the values of two variables, the two variables have a variety of types, which can be int, float, char, bool and so on. We need to pass the address of the variable into the function through the parameter. In C language, programmers often need to design three functions with different names respectively, whose function prototype is similar to the following ones.)