用vector（向量）实现动态开辟二维三维数组，这里vector中元素的内存的地址分配也有同双指针实现的二维数组有同样的特点。不过用vector的方法比使用双指针简单地多，分配内存空间时会更安全，数组初始化代码也更简单，所以本人建议使用STL中的vector来实现变长多维数组。-Implemented with vector (vector) opened a two-dimensional dynamic three-dimensional array, the memory address where the distribution of elements in the vector are also two-dimensional array with dual pointers achieve the same characteristics. But with the vector approach than simply using double pointer, will be safer when allocating memory space, the array initialization code more simple, so I recommend using the STL vector to achieve variable-length multidimensional arrays.