# HP Forums

Full Version: (11C) Finding biggest of 3 integers
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Program to find the biggest number of 3 integers.

Procedure: f [USER]

n1 [ENTER] n2 [ENTER] n3 [E]

Example:

1, 3 and 2

1 [ENTER] 3 [ENTER] 2 [E] display 3

Biggest number is 3

---------------------------------------

14, 10 and 8

14 [ENTER] 10 [ENTER] 8 [E] display 14

--------------------------------------

-4, -3 and -6

4 [CHS] [ENTER] 3 [CHS] [ENTER] 6 [CHS] [E] display -3

-------------------------------------

FIX 4

0.9987, 0.9990 and 0.9989

,9987 [ENTER] ,9990 [ENTER] ,9989 [E] display 0.9990

Program: Finding biggest of 3 integers
Code:

LBL E
STO 1
Rv
STO 2
Rv
STO3
------------------------------------------
RCL 2
RCL 1
X>Y
GTO 2
RCL 3
RCL 2
X>Y
GTO 1
RCL 3
RTN
------------------------------
LBL 1
RCL 2
RTN
-------------------------------
LBL 2
RCL 3
RCL 1
X>Y
GTO 3
RCL 3
RTN
------------------------------
LBL 3
RCL 1
RTN

Gamo
(10-20-2018 05:41 AM)Gamo Wrote: [ -> ]Program to find the biggest number of 3 integers.

Of any three numbers, not only integers.

Gamo, do you remember the following sequence?

With two numbers in X and Y, X≤Y? X<>Y checks if X is the smaller of the two. If it is, both are swapped.
So this sequence always returns the larger number in X and the smaller one in Y.

Likewise, X>Y? X<>Y returns the smaller number in X and the larger one in Y.

Now assume there are three different numbers in X, Y and Z.
X>Y? X<>Y will put the larger one in Y and the smaller one in X.

Roll down the stack one level to compare this larger number with the third one.
X≤Y? X<>Y will put the largest of all three in X.

So the program simply is:

Code:
01 LBL A
02 X>Y?
03 X<>Y
04 R↓
05 X≤Y?
06 X<>Y
07 RTN

Or on the 12C and others without an X>Y? test:

Code:
01 X≤Y?
02 X<>Y
03 X<>Y
04 R↓
05 X≤Y?
06 X<>Y
07 GTO 00

You can easily extend this example. This is what we get:

Return the largest of two numbers:
Code:
01 LBL A
02 X≤Y?
03 X<>Y
04 RTN

Return the largest of three numbers:
Code:
01 LBL A
02 X>Y?
03 X<>Y
04 R↓
05 X≤Y?
06 X<>Y
07 RTN

Return the largest of four number:
Code:
01 LBL A
02 X>Y?
03 X<>Y
04 R↓
05 X>Y?
06 X<>Y
07 R↓
08 X≤Y?
09 X<>Y
10 RTN

Dieter
Thanks Dieter