Oops, should of read the rest of the thread first.
Already been answered using my solution ;)

I didnt think to check all the way through the replies, figured if there was one, it would be in the top layer or replies.



>>For those who know about asymptotic behavior:
>>
>>Given an array of increasing numbers and a number X, create a linear algorithm that finds whether the array contains two numbers that sum to X (and those two numbers if they exist).
>>
>>Daniel
>
>
>How about
>

>LPARAMETER nFind
>
>LOCAL nFront, nBack, nSum
>
>DIMENSION a[10]
>a[1]= 3
>a[2]= 5
>a[3]= 7
>a[4]= 9
>a[5]= 10
>a[6]= 12
>a[7]= 14
>a[8]= 16
>a[9]= 18
>a[10]= 20
>
>nFront= 1
>nBack= ALEN(a)
>
>nSum= a[nFront] + a[nBack]
>DO WHILE nSum != nFind AND nFront != nBack
>	IF nSum > nFind
>		nBack = nBack - 1
>	ENDIF
>	IF nSum < nFind
>		nFront= nFront + 1
>	ENDIF
>	nSum= a[nFront] + a[nBack]
>ENDDO
>
>IF nFront != nBack
>	? a[nFront], a[nBack]
>ELSE
>	? "Not Found"
>ENDIF
>

>
>Keep a pointer to the front, and one to the back, If the sunm is greater, move the back pointer in one, if the sum is less move the front pointer in one.