,max函数出现在main函数之前,因此在main函数中调用max函数时,编译系统能识别max是已定义的函数名｡ 如果把两个函数的位置对换一下,即先写main函数,后写max函数,这时在编译main函数遇到max时,编译系统无法知道max代表什么含义,因而无法编译,按出错处理｡

为了解决这个问题,在主函数中需要对被调用函数作声明-, Max function appears before the main function, so when you call max function in the main function, the compiler system can identify max is defined function name if the position of the two functions of a change, the main function of which is to write, write max function, then encountered when compiling the main function max, max compilation system can not know what the meaning of, and therefore can not be compiled, according to error handling. To solve this problem, in the main function called function needs to make a statement