动态数组怎样创建 new和delete实现动态内存分配

new

delete

new

new 类型[大小]

int size;
std::cout << "输入数组大小: ";
std::cin >> size;

int* arr = new int[size];  // 创建大小为 size 的动态数组

int* arr = new int[size]{};  // 所有元素初始化为 0
// 或者
int* arr = new int[5]{1, 2, 3, 4, 5};  // 初始化前5个元素

delete[]

delete[]

delete

delete[] arr;  // 释放整个数组
arr = nullptr; // 避免悬空指针

delete

delete[]

#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "请输入数组长度: ";
    cin >> n;

    // 动态创建数组
    int* arr = new int[n];

    // 输入数据
    for (int i = 0; i < n; ++i) {
        cout << "输入第 " << i + 1 << " 个数: ";
        cin >> arr[i];
    }

    // 输出数据
    cout << "你输入的数组是: ";
    for (int i = 0; i < n; ++i) {
        cout << arr[i] << " ";
    }
    cout << endl;

    // 释放内存
    delete[] arr;
    arr = nullptr;  // 好习惯：避免野指针

    return 0;
}

int* arr = new(std::nothrow) int[size];
if (arr == nullptr) {
    std::cout << "内存分配失败！" << std::endl;
    return -1;
}

new

delete

std::vector

#include <vector>
std::vector<int> arr(n);  // 自动管理内存，不会泄漏

new

delete[]

std::vector