C programming question about mergesort.

Using C code complete the mergesort function shown below, your function must be implemented iteratively (i.e. using loops instead of recursion). You can assume the existence of a merge function with the following header (i.e. you don't have to write the merge function, and can call it in your mergesort function). Using C code write a merge function that merges two sorted arrays, not sub-arrays of the same array, into a single sorted array and that returns a pointer to the resulting merged array. Your function should have parameters for the two input arrays and their lengths