length of 2d array c++ code example

Example 1: length of 2d array c++

int rows = sizeof(arr) / sizeof(arr[0]); // returns rows
int col = sizeof(arr[0]) / sizeof(int); // returns col

Example 2: size of a matrix c++

std::vector< std::vector<int> > my_array; /* 2D Array */

my_array.size(); /* size of y */
my_array[0].size(); /* size of x */