insertion sort algo

[nikhil124]

consider this insertion sort algo(from cormen)
INSERTION-SORT(A)

    for j<--- 2 to length[A]
        do key<--- A[j]
        >Insert A[j] into the sorted seq A[1......j-1].
        i <---  j -1
        while i > 0 and A[i] > key 
            do A[i+1]<--- A[i]
            i <--- i - 1
        A[i+ 1] <--- key

i'm unable to understand from line 6 to 8.
in 6) we put value of A[i] in A[i+1] , then again we put value of "key " in A[i+1] in line 8).How's that possible.what is the meaning of line 7) i'm unable to interpret it.
plz help, where i'm making mistake

[Banfa]

The whole thing makes more sence with the white space preserved so the structure is clear. I have edited your post to do this. Also not this sudo code starts arry/list indexes at 1.

Lines 6 and 7 are responsible for moving the correct part of the currently sorted list down 1 item at a time until a space is made for the item currently being sorted at the correct location to maintain the sorting.

Line 8 then puts the item currently being sorted into that space.

For example imagine we are sorting the list

1, 3, 5, 7, 4, <OtherData>

and j is 5

key = A[j] = 4

After running the loop in lines 4 - 7 the list looks like this

1, 3, 5, 5, 7, <OtherData>

and i has a value of 2

Line 8 reinserts the key at i+1

A[i+1] = key = 4

And the list finishes that iteration as

1, 3, 4, 5, 7, <OtherData>

ready to sort the <OtherData>