Write a function that takes in an n x m 2D array(that can be square-shaped when n == m) and returns a 1D array of all the array's elements in zig zag order. Zigzag ...

Program to add, delete, insert, append, pop an element from an array and to find the index of the element of in a 1D, 2D array and in list. -> 001 is program in 1D array. -> 002 is program in 2D array ...