[C++] 变量、指针、引用作函数参数的区别

//============================================================================ // Name : CppLab.cpp // Author : sodino // Version : // Copyright : Your copyright notice // Description : Hello World in C++,Ansi-style //============================================================================ #include <iostream> #include <string> using namespace std; struct Student{ string name; }; int main() { void print(Student); void print_point(Student *); void print_reference(Student &); struct Student stu = {"Yao ming"}; cout << "main &stu=" << &stu << endl << endl; print(stu); cout << "after print() name=" << stu.name << " no changed."<< endl << endl; print_point(&stu); cout << "after print_point() name=" << stu.name << " has been modified." << endl << endl; print_reference(stu); cout << "after print_reference() name=" << stu.name << " has been modified." << endl; return 0; } void print(Student stu) { // 实参转形参，会消耗额外的时间。print_reference()则效力高许多。 cout << "print() stu address=" << &stu << " is different."<< endl; // 形参stu与函数体外的stu是两个不同的对象！！ stu.name = "new.name"; // 这里的赋值其实不会改变函数体外stu的name cout << "print() set new name=" << stu.name << endl; } void print_point(Student * stu) { stu->name = "new.point.name"; cout << "print_point() set new name=" << stu->name << endl; } void print_reference(Student &stu) { stu.name = "new.reference.name"; cout << "set new name=" << stu.name << endl; }