c++ vector的使用

// #include "lib/sundry.hpp"
#include <future>
#include <iostream>
#include <vector>

using namespace std;

void test01() {
    vector<int> v1;
    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    v1.push_back(40);

    vector<int>::iterator it = v1.begin();  // 保存起始迭代器
    for(; it!=v1.end(); it++) {
        cout << *it << " ";
    }
    cout << endl;
    cout << "test01 end ... " << endl;
}
void test02() {
    vector<int> v1;
    v1.reserve(500);    // 直接预留500的空间.
    cout << "容量: " << v1.capacity() << " , 大小: " << v1.size() << endl;
    vector<int>::iterator it = v1.begin();

    int i = 0;
    int count = 0;
    for(i=0;i<10000;i++) {
        v1.push_back(i);
        if (it != v1.begin()) {
            count++;
            cout << "第" << count << "次开辟空间, 容量: " << v1.capacity()
                    << " , 大小: " << v1.size() << endl;
            it = v1.begin();
        }
    }
    cout << "test02 end ... " << endl;
}

void printVectorInt(vector<int> &v) {
    vector<int>::iterator it = v.begin();
    for(;it != v.end();it++) {
        cout << *it << " ";
    }
    cout << endl;
}

void test03() {
    vector<int> v1(5, 100); // 初始化5个100
    printVectorInt(v1);

    vector<int> v2(v1.begin(), v1.end());
    printVectorInt(v2);

    vector<int> v3;
    v3.assign(10, 10);
    printVectorInt(v3);

    v3.swap(v2);  // 交换两个vec
    printVectorInt(v3);
    printVectorInt(v2);

    cout << "test03 end ... " << endl;
}

// 收缩空间
void test04() {
    vector<int> v1;
    v1.reserve(1000);
    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    cout << "容量: " << v1.capacity() << " , 大小: " << v1.size() << endl;

    // 通过v1初始化匿名变量，只会初始化实际内容部分，未使用的容量会被丢弃, 然后和v1交换.
    // 达到收缩的结果.
    vector<int>(v1).swap(v1);
    cout << "vec收缩后容量: " << v1.capacity() << " , 大小: " << v1.size() << endl;

    cout << "test04 end ... " << endl;
}

// 二维数组遍历
void test05() {
    vector<int> v1(5, 10);
    vector<int> v2(5, 100);
    vector<int> v3(5, 1000);

    // 定义一个vector容器，存放v1,v2,v3
    vector< vector<int> > v;
    v.push_back(v1);
    v.push_back(v2);
    v.push_back(v3);

    // 遍历
    vector< vector<int> >::iterator it = v.begin();
    for(; it != v.end(); it++) {
        vector<int>::iterator mit = (*it).begin();
        for (; mit!=(*it).end(); mit++) {
            cout << *mit << " ";
        }
        cout << endl;
    }

    cout << "test05 end ... " << endl;
}

// stl算法对vector容器排序
#include<algorithm>
void test06() {
    vector<int> v1;
    v1.push_back(10);
    v1.push_back(3);
    v1.push_back(49);
    v1.push_back(2);
    printVectorInt(v1);

    // 排序算法
    sort(v1.begin(), v1.end());
    printVectorInt(v1);

    cout << "test06 end 排序算法 sort ... " << endl;
}

#include<string>
class Person{
    friend void printVectorPerson(vector<Person> &v);
    friend bool comparePerson(Person ob1, Person ob2);
private:
    int num;
    string name;
    float score;
public:
    Person(){}
    Person(int num, string name, float score) {
        this->num = num;
        this->name = name;
        this->score = score;
    }
};

// 打印自定义的vec
void printVectorPerson(vector<Person> &v) {
    vector<Person>::iterator it = v.begin();
    for (; it != v.end(); it++) {
        cout << (*it).num << " " << (*it).name << " " << (*it).score << endl;
    }
}

// 定义vec排序规则
bool comparePerson(Person ob1, Person ob2) {
    return ob1.num < ob2.num;
}

void test07() {
    vector<Person> v1;
    v1.push_back(Person(100, "luck", 55.4f));
    v1.push_back(Person(120, "luckee", 35.4f));
    v1.push_back(Person(10, "luckdd", 3.4f));
    v1.push_back(Person(20, "luckaa", 90.4f));
    printVectorPerson(v1);

    // 对自定义类型vec的排序需要指定排序规则.
    sort(v1.begin(), v1.end(), comparePerson);
    printVectorPerson(v1);

    cout << "test07 end ... " << endl;
}

int main() {
    test01();
    test02();
    test03();
    test04();
    test05();
    test06();
    test07();
    return 0;
}