How do I find the size of a 2 dimensional vector? So far I have the following code which doesn't compile.
#include <iostream> #include <vector> using namespace std; int main() { vector < vector <int> > v2d; for (int x = 0; x < 3; x++) { for (int y = 0; y < 5; y++) { v2d.push_back(vector <int> ()); v2d[x].push_back(y); } } cout<<v2d[0].size()<<endl; cout<<v2d[0][0].size()<<endl; return 0; }
vector_name. size() gives you the numbers of column in a 2D vector and vector_name[0]. size() gives you the numbers of rows in a 2D vector in C++.
A 2-Dimensional vector is used in C++ programming to store and access data based on rows and columns. Different ways to create a 2-Dimensional vector have been shown in this tutorial by using simple examples.
Size of a matrix = number of rows × number of columns. It can be read as the size of a matrix and is equal to number of rows “by” number of columns.
To get the size of v2d, simply use v2d.size(). For size of each vector inside v2d, use v2d[k].size().
Note: for getting the whole size of v2d
, sum up the size of each individual vector, as each vector has its own size.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With