指针和引用的基本用法

#include <iostream>
using namespace std;

int* func(int& ref) {
    ref = 100;  // 修改引用所引用对象的值
    int* ptr = &ref;
    return ptr;
}

int& func_2(int* ptr) {
    *ptr = 200;  // 通过指针修改值
    return *ptr;  // 返回引用
}

int main()
{

    int num = 10;
    int& ref = num;  // 定义一个引用，引用 num
    int* ptr = &ref; // 定义一个指针，指向引用所引用的对象，即 num

    cout << "num " << num << endl;//10
    cout << "ref " << ref << endl;//10
    cout << "*ptr " << *ptr << endl;//10

    *ptr = 20;  // 通过指针修改值
    cout << "num " << num << endl;//20
    cout << "ref " << ref << endl;//20
    cout << "*ptr " << *ptr << endl;//20

    int tmp = 30;
    int *result= func(tmp);
    cout << "tmp " << tmp << endl;//100
    cout << "*result " << *result << endl;//100

    int i32num = 150;
    int& ret = func_2(&i32num);  //传入指针
    cout << "i32num " << i32num << endl;//200
    cout << "ret " << ret << endl;//200
}