#include ＜vector＞应用

 在看这篇文章之前，先看看#include <vector>的简介。

 #include <vector>

这篇文章我来给大家几个vector的应用。

应用

应用1

#include <iostream>
#include <vector>
int main() {
    // 声明一个存储整数的 vector
    std::vector<int> numbers;
    // 添加元素
    numbers.push_back(10);
    numbers.push_back(20);
    numbers.push_back(30);
    // 输出 vector 中的元素
    std::cout << "Vector contains: ";
    for (int i = 0; i < numbers.size(); ++i) {
        std::cout << numbers[i] << " ";
    }
    std::cout << std::endl;
    // 添加更多元素
    numbers.push_back(40);
    numbers.push_back(50);
    // 再次输出 vector 中的元素
    std::cout << "After adding more elements, vector contains: ";
    for (int i = 0; i < numbers.size(); ++i) {
        std::cout << numbers[i] << " ";
    }
    std::cout << std::endl;
    // 访问特定元素
    std::cout << "The first element is: " << numbers[0] << std::endl;
    // 清空 vector
    numbers.clear();
    // 检查 vector 是否为空
    if (numbers.empty()) {
        std::cout << "The vector is now empty." << std::endl;
    }
    return 0;
}

应用二

#include <iostream>
#include <vector>

int main() {
    std::vector<int> vec = {1, 2, 3};
    try {
        std::cout << vec.at(2) << std::endl;  // 正常输出
        std::cout << vec.at(5) << std::endl;  // 超出范围，抛出异常
    } catch (const std::out_of_range& e) {
        std::cout << "Exception: " << e.what() << std::endl;
    }
    return 0;
}

应用三

#include <iostream>
#include <vector>
int main() {
    std::vector<int> vec;
    vec.push_back(10);
    vec.push_back(20);
    vec.push_back(30);
    std::cout << "Vector size: " << vec.size() << std::endl;
    std::cout << "Vector capacity: " << vec.capacity() << std::endl;
    // 删除最后一个元素
    vec.pop_back();
    std::cout << "After pop_back, size: " << vec.size() << std::endl;
    return 0;
}