initialize vector to 0 c++ code example

Example 1: initialize 2d vector of ints c++

auto M = 4;	// num of rows
auto N = 3; // num of cols in each row
auto default_value = 1; // default value of all int elements
std::vector<std::vector<int>> matrix(M, std::vector<int>(N, default_value));

Example 2: how to initialize vector in c++ with all elements 0

vector<int> arr(10,0);