在矩阵对象C++上移动时出现索引错误

#include <iostream>
#include <vector>

int main() {
    int rows = 3;
    int cols = 3;
    std::vector<std::vector<int>> matrix(rows, std::vector<int>(cols, 0));

    // 初始化矩阵
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            matrix[i][j] = i * cols + j;
        }
    }

    int row = 3;
    int col = 1;

    if (row >= 0 && row < rows && col >= 0 && col < cols) {
        // 安全访问矩阵元素
        int element = matrix[row][col];
        std::cout << "Element at (" << row << ", " << col << ") is " << element << std::endl;
    } else {
        // 处理索引错误
        std::cerr << "Index out of bounds!" << std::endl;
    }

    return 0;
}