Please explain the below line

vector<vector >arr{{2,6,12,15},{1,3,14,20},{3,5,8,10}};

1.)first vector means that we are creating a vector
2.) second vector means that we are creating another vector inside the vector and the value 2nd vector will accept is int type …

till now i am getting

but after that 1st vector bracket is closed > which means we are outside the vector and outside of the vector body we have given name to the vector which is arr

i am not getting it that why we have given the name of vector after closing the bracket which is >

???
please explain
why are we writing the name of vector outside the < > ???

hi ankush,
vector<vector> arr; is similar to array[][].
Its syntax of 2D vector just like 2D array.
{{2,6,12,15},{1,3,14,20},{3,5,8,10}};
its matrix form will be like
2 6 12 15
1 3 14 20
3 5 8 10
Please let me know if there is any other doubt.