vector中常用的API函数

#include <iostream>
#include <vector>

using namespace std;




int main() {
    vector<int> v = {7, 5, 6, 3, 2, 9, 0};

    v.push_back(44);
    v.push_back(129);  // 尾部插入新元素
    v.pop_back();  // 删除v尾部元素
    
    // 检查v中是否有元素，v为空时返回true，v为非空时返回false
    cout << "v.empty() = " << v.empty() << endl; 

    // 返回v中的元素个数
    cout << "v.size() = " << v.size() << endl;

    // 返回v中的第一个元素
    cout << "v.front() = " << v.front() << endl;

    // 返回v中的最后一个元素
    cout << "v.back() = " << v.back() << endl;

    // 遍历v中的所有元素
    for(int n : v) {
        cout << "n = " << n << endl;
    }

    cout << "===============1===============\n";
    //  赋值运算和move()
    vector<int> v1;
    v1 = v;
    for(int n1: v1) {
        cout << "n1 = " << n1 << endl;
    }

    cout << "===============2===============\n";
    vector<int> v2;
    v2 = move(v);
    // move()后，原始v中的数据被移动到v2中，v中已无元素
    cout << "v.size() = " << v.size() << endl;

    for(int n2: v2) {
        cout << "n2 = " << n2 << endl;
    }

    cout << "===============3===============\n";
    // 访问元素
    vector<int> d = {5, 2, 1, 0, 8, 9};
    // 修改d[1]的值
    d.at(1) = 666;
    for(int e : d) {
        cout << "e = " << e << endl;
    }
    // 索引超过范围，抛出out of range异常
    try {
        d.at(10) = 999;
    }
    catch (out_of_range const& exec){
        cout << exec.what() << endl;
    }

    // 赋值d1
    vector<int> d1;
    d1.assign(9, 5);  // d1 = {5, 5, 5, 5, 5, 5, 5, 5, 5}
    for(int e1 : d1) {
        cout << "e1 = " << e1 << endl;
    }
    cout << "===============4===============\n";
    
    d1.assign({1, 2, 3, 4, 5});
    for(int e1 : d1) {
        cout << "e1 = " << e1 << endl;
    }
    cout << "===============5===============\n";
    
    // 迭代器begin()和end()
    for(vector<int>::const_iterator iter = d.begin(); iter != d.end(); iter++) {
        cout << "e2 = " << *iter << endl;
    }
    cout << "===============6===============\n";
    
    // 迭代器rbegin()和rend()
    for(vector<int>::reverse_iterator iter = d.rbegin(); iter != d.rend(); iter++) {
        cout << "e2 = " << *iter << endl;
    } 

    // capacity():返回d中元素个数
    cout << "===============7===============\n";
    cout << "d.capacity() = " << d.capacity() << endl;

    // clear():清除d中的内容
    cout << "===============8===============\n";
    d.clear();
    cout << "d.size() = " << d.size() << endl;

    // insert():插入元素
    cout << "===============9===============\n";
    
    for(int n2: v2) {
        cout << "n2 = " << n2 << endl;
    }

    return 0;
}