Exercise #1

Write a program that reads in 10 numbers and prints them out in the reverse order that they were input. Surprise, use an array!

Hint: You can use the array to store the numbers when you are reading them in and then access the array from the highest index to the lowest to output them in reverse order.

Exercise #2

Now I want you to actually reverse the elements in the array itself.
Then cout the array.
You can only use one array.

Hint: Start at boths ends of the array and interchange (or swap) the end elements. Then work your way to the center of the array, swapping as you go. When you've reached the middle of the array, you're finished. So, we're going to swap the first element with the last element, and then the second element with the second to last element, and then the third element with the third to last element, etc. This continues until we are at the middle of the array. So the loop, indexed by ``i'' starts at the beginning of the array and ends at the halfway mark.

Exercise #3

Suppose that you have a list of integer numbers stored in ascending order in an array. Suppose also that the array is not full (i.e., there are unused elements at the end of the array). Consider the problem of inserting a new number into the middle of the list. This is not as straightfoward to do as it sounds because the sorted order of the list must be maintained. For example. if the list contains the even integers between 0 and 20, and you want to insert the number 7 into this list, it must be inserted as the fifth number in the list (position 4) to keep the order correct (see figure below). If the list is stored as an array in your program, then the the number 8 is already stored at subscript position 4 in the array.

The solution is to move all the numbers in position 4 and after, one position higher in the array. Thus, the number 20 is moved from position 10 to position 11, the number 18 is moved from position 9 to postion 10, the number 16 is moved from position 8 to position 9,..., and the number 8 is moved from position 4 to position 5. Now position 4 is vacant and can be used to insert the number 7, keeping the array in sorted order.

I have started a program for you that has an array of numbers declared and initialized. It then asks the user to enter a new number to insert into the list and the subscript of where the number is to be inserted in the list. In the example above, the user would enter 7 and 4 to indicate that the number 7 should be inserted in the array at position 4. Finally, the program prints the new list with the inserted number.

The program does not contain the code needed to do the insertion. Your job is to complete the program by adding this code. Use the technique illustrated above. Note that variable N tells you the number of integers in the list (they have positions that run from 0 through N-1). Don't forget to increment N when you insert the new number since the list is now one element longer.

When you write the code required to move numbers in the array elements following the insertion point one element to the right, be careful how you do it. In the example above, the 20 must be moved first, then the 18, then the 16, etc. If you try to move the 8 first, you will lose data.

The path to the parital program is: ~escobj/public/ex2.C