实验5

//6-17 改: 
#include <iostream>
using namespace std;
int main(){
    int a,*p=&a;
    *p=9;
    cout<<"The value at p: "<<*p;
    return 0;
}
 

//6-18 
#include <iostream>
using namespace std;
int fn1(){
    int *p=new int (5);
    return *p;
    delete p;
}
int main(){
    int a=fn1();
    cout<<"the value of a is: "<<a;
    return 0;
}
//delete 用来删除由new建立的对象 

//ex3.cpp
#include <iostream>
#include <vector>
#include <string>
using namespace std;

// 函数声明 
void output1(vector<string> &);  
void output2(vector<string> &);  

int main()
{
    vector<string>likes, dislikes; // 创建vector<string>对象likes和dislikes
    likes.push_back( "favorite book" );
    likes.push_back(" music");
    likes.push_back("film");
    likes.push_back("paintings");
    likes.push_back("anime");
    likes.push_back("sport");
    likes.push_back("sportsman");
    likes.push_back("etc");
    cout << "-----I like these-----" << endl; 
    
    output1(likes);
    dislikes.push_back("running");
    dislikes.push_back("studying");
    dislikes.push_back("etc");
    cout << "-----I dislike these-----" << endl;
    output1(dislikes);
    swap(likes, dislikes);
    cout << "-----I likes these-----" << endl;
    output2(likes);
    cout << "-----I dislikes these-----" << endl;
    output2(dislikes);
    return 0;
}


// 函数实现 
// 以下标方式输出vector<string>数组对象v的元素值  
void output1(vector<string> &v) {
    for (int i = 0; i<v.size(); i++)
        cout << v[i] << endl;
}

// 函数实现
// 以迭代器方式输出vector<string>数组对象v的元素值 
void output2(vector<string> &v) {
    vector<string>::iterator itr = v.begin();
    for (itr; itr != v.end(); itr++)
        cout << *itr << endl;
}