identifying the corresponding node number to each element for meshed geometry.

i used a triangular geometric order to mesh the geometry i have. but i need a matrix of the element and node number associated with it . how can i do that? for example if element 1 is bounded by node 1,2 and 3; and also element 2 is bounded by 2, 3 and 4 node numbers.....i need the matrix be like [1 2 3;2 3 4]..................................