CPP ：array

array 是一种固定大小的容器

测试代码

#define debug2(a,b) cout<<#a<<" = "<<a<<' '<<#b<<" = "<<b<<endl;
#include<bits/stdc++.h>
using namespace std;
int main(){
    const int n = 5;
    // 定义方式
    //array<type, const int> name;
    // array<int, 5> arr = {1, 3, 4, 6, 9}; or array<int, 5> arr {1, 3, 4, 6, 9};
    array<int, n> arr {1, 3, 4, 6, 9};

    // arr.push_back(1); 错误 X

    //遍历方式
    for(int i : arr) cout << i << ' '; cout << '\n';
    for(int i = 0; i < n; i++) cout << arr[i] << " \n"[i == n - 1];
    for(auto i = arr.begin(); i != arr.end(); i++) cout << *i << ' '; cout << '\n';
    for(auto i = arr.rbegin(); i != arr.rend(); i++) cout << *i << ' '; cout << '\n';
    for(int i = 0; i < n; i++) cout << arr.at(i) << " \n"[i == n - 1];

    //可以使用front 和 back
    debug2(arr.front(), arr.back());

    //可以使用swap
    array<int, 2> x {2, 4}, y {20, 40};
    swap(x, y);
    for(int i : x) cout << i << ' '; cout << '\n';

    //empty, size, max_size
    array<int, 5> b5; array<int, 0> b0;
    debug2(b0.empty(), b5.empty());
    //因为array是固定大小的容器，所以size = max_size
    debug2(b5.size(), b5.max_size());

    return 0;
}

输出结果

1 3 4 6 9 
1 3 4 6 9
1 3 4 6 9 
9 6 4 3 1 
1 3 4 6 9
arr.front() = 1 arr.back() = 9
20 40 
b0.empty() = 1 b5.empty() = 0
b5.size() = 5 b5.max_size() = 5