这个是一个C++ 代码，功能是输入四个正整数，根据这四个正整数的任意排列，每个整数只能够使用一遍，任意使用加减乘除，找到一个可以计算成24的方法，输出计算方法(This is a C++ code function is to input four positive integers, according to any of the four positive integer permutation, each integer can be used only once, any use to find a add, subtract, multiply and divide, calculated as 24 method, calculation method canbe output)