当您不知道大小时,如何初始化二维数组

#include<iostream>
#include<vector>

int main() {
    int rows, cols;
    std::cout << "Enter the number of rows: ";
    std::cin >> rows;
    std::cout << "Enter the number of columns: ";
    std::cin >> cols;

    std::vector<std::vector<int>> array(rows, std::vector<int>(cols));

    // 初始化数组
    for (int i = 0; i< rows; i++) {
        for (int j = 0; j< cols; j++) {
            array[i][j] = i * j;
        }
    }

    // 输出数组
    for (int i = 0; i< rows; i++) {
        for (int j = 0; j< cols; j++) {
            std::cout<< array[i][j] << " ";
        }
        std::cout<< std::endl;
    }

    return 0;
}