C++ vector迭代器访问二维数组

#include<iostream>
#include<vector>

int main(){
    std::vector<int> arr();  // 创建一维数组
    for(int i=;i<;++i)
    std::cout << arr[i]<<" ";
    std::cout << std::endl;
    std::cout << std::endl;

    std::vector<int> arr1(,);
    for(std::vector<int>::const_iterator i=arr1.begin();i!=arr1.end();++i){
        std::cout << *i<<" ";
    }
    std::cout << std::endl;
    std::cout << std::endl;

    std::vector<std::vector<int>> arr2(,std::vector<int>(,));  // 创建二维数组
    for(int i=;i<;++i){
        for(int j=;j<;++j) std::cout << arr2[i][j]<<" ";
        std::cout <<std::endl;
    }
    std::cout << std::endl;

    std::vector<std::vector<int>>::iterator toarr2;
    std::vector<int>::iterator it;
    for(toarr2 =arr2.begin(); toarr2 != arr2.end(); ++toarr2){
        for(it=(*toarr2).begin(); it != (*toarr2).end();++it){
            std::cout << *it<<" ";
        }
        std::cout << std::endl;
    }
    std::cout << std::endl;

    return ;
}