Write a function called bubble_sort() that accepts an array of pointers to strings and the number of strings as arguments, and returns nothing. The function sorts the strings according to the following algorithm:

1. set the marker U for the unsorted section at the end of the list (U is an integer index value)

2. while the unsorted section has more than one element do steps 3 through 7

3. set the current element marker C at the second element of the list (C is an integer index value)

4. while C has not passed U do steps 5 and 6

5. if the item at position C is less than the item to its left then exchange these two items

6. move C to the right one position

7. move U left one position

8. stop

Your implementation for this function may NOT use strcpy(). You may only exchange or swap pointers, but NOT actually make copies of the strings!