Algorithm Help (1 Viewer)

[sikeveo]

.

 

[fatmuscle]

ur missing an END IF

 

[fatmuscle]

sorry, i mucked around with ur post so it's indented.

 

[gress]

BEING MAINPROGRAM

INITIALISATION
set ReqPts to 9
set each players points to 0
END INITIALISATION

toss and decide server
REPEAT
server serves the ball
REPEAT
play the rally
UNTIL rally is won
IF server wins rally THEN
increment server's points by 1
ELSE
swap player status
ENDIF
UNTIL a player has won ReqPts
declare winner
END MAINPROGRAM

BEING SUBPROG toss and decide server
toss a coin
IF heads THEN
player 1 is the server
player 2 is the recieiver
ELSE
player 2 is the server
player 1 is the receiver
ENDIF
END SUBPROG toss and decide server

I'd indent if I knew how but..
This is in my year 12 sdd notes, theres no way I wrote this myself so [not really my style] so credit goes to whoever I copied it off or wherever I got it from. (internet maybe?)

so yeah.. hope that helps

 

[SamD]

1. What's the point of the INITIALISE Variables line, its irrelevant as this is what the next two lines do.
2. What does Coin Toss mean, presumably determines who serves. You need to detail this somehow.
3. What does Play game mean when it's within a loop. Seems to me this inside Repeat is unnecessary, you could have just said Play Point or similar.
4. Your technique for adding points to the server's score is a mess. How is the value in ServerScore shoved back into the relevant Playerscore? I'd suggest using an array with two elements, one for each player.
5. More detail needed to explain Switch Player Status, no idea how this is done at present. If you use an array then you just change 0 to 1 or 1 to 0 to do this.

Marks wise I'd say you'd get about 60%

HTH
Sam

 

[sikeveo]

hmm, im completely lost at what was said in the above post, anyone care to lead by example? I know how to detail the toss coin one, but im lost with how to add the points a better way and using an array. And how would u change the player status using an array?
thanks guys

ps. im in yr11 so still 60%?

 

[sikeveo]

i just added the subprogram, so that fixes up the coin toss thingy.

 

[fatmuscle]

BEGIN Main
>>Set Player1score and Player2score to 0
>>Set ServerScore to 0

>>Coin Toss
>>WHILE Player1score < 9 AND Player2score < 9
>>>>Server serves ball
>>>>REPEAT
>>>>>>IF Server is Player1 THEN
>>>>>>>>ServerScore = Player1score
>>>>>>ELSE
>>>>>>>>ServerScore = Player2 score
>>>>>>ENDIF
>>>>>>Play game
>>>>UNTIL Rally is won by player
>>>>IF Server wins game THEN
>>>>>>ServerScore = ServerScore + 1
>>>>ELSE
>>>>>>Switch player status
>>>>ENDIF
>>ENDWHILE
>>Declare winner
>>Give trophy
END Main


Begin Sub Coin Toss
>>Player 1 Choose Side
>>Player 2 Choose Side
>>Toss Coin
>>IF Player 1s side is face up THEN
>>>>Player 1 is the server
>>>>Player 2 is the receiver
>>ELSE
>>>>Player 2 is the server
>>>>Player 1 is the receiver
>>END IF
END Sub Coin Toss

 

[sikeveo]

thanks for the indentation mate!

 

[SamD]

Originally posted by SamD
2. What does Coin Toss mean, presumably determines who serves. You need to detail this somehow.

If you use an array then Player1Score and Player2Score could become PlayerScore(Server) where Server is either 0 or 1. Now you can toss the coin and if Head then Server=0 else Server=1.

3. What does Play game mean when it's within a loop. Seems to me this inside Repeat is unnecessary, you could have just said Play Point or similar.

The question asks to "describe how to score a ball game", so its unecessary to have this repeat loop at all. Furthermore I can't see how your IF statement within this loop works. Just trash the whole loop and replace with Play Rally.

4. Your technique for adding points to the server's score is a mess. How is the value in ServerScore shoved back into the relevant Playerscore? I'd suggest using an array with two elements, one for each player.

If you use an array as above then after each rally your IF becomes: IF Server wins rally THEN add 1 to PlayerScore(Server) ELSE Swap Server.

5. More detail needed to explain Switch Player Status, no idea how this is done at present. If you use an array then you just change 0 to 1 or 1 to 0 to do this.

If using an array then swapping server really means changing the value of the variable Server from 0 to 1 (or viceversa). Could just be Server=(Server+1) MOD 2.

HTH
Sam

 

[sikeveo]

is this right?


BEGIN Main
> Define PlayerScore(Server) as array
Set PlayerScore(Server) to 0

>>Coin Toss
>>WHILE PlayerScore(Server) < 9
>>>>Server serves ball
>>>>>>Play point
>>>>IF Server wins point THEN
>>>>>>PlayerScore(Server) = PlayerScore(Server) + 1
>>>>ELSE
>>>>>> Server=(Server+1) MOD 2
>>>>ENDIF
>>ENDWHILE
>>PlayerScore(Server) = Winner
END Main


Begin Sub Coin Toss
>>Toss Coin
>>IF Heads THEN
>>>>Server = 0
>>ELSE
>>>>Server = 1
>>END IF
END Sub Coin Toss

 

[fatmuscle]

use the [ color = white ] and [ / colour ] tags to hide the >>>

 

[SamD]

Heaps better! Your in Band 5 now!!

To get into Band 6 consider the following:

1. You don't need to define data structures in algorithms, so trash that line.
2. Your PlayerScore(Server)=0 is vague. You should initialise both PlayerScores explicitly. ie. PlayerScore(0)=0 and PlayerScore(1)=0.
3. PlayerScore(Server)=Winner is wrong. The winner is the current Server. So something like Winner is Server, or to map 0,1 to player 1,2 you could have Winner is Server+1.
4. Finally, fix up your indenting... or is it just how it looks in this post. I doubt you'd lose marks for this but it makes it easier for the marker.

HTH
Sam

 

[Winston]

Yeah it looks much better, and i think you missed some minor thing

Coin Toss, must be underlined, as you are calling a sub-routine.

 

[fatmuscle]

ha! i dind't miss that

but then again, i even bolded key words

 

[sikeveo]

hey thanks guyz

 

[fatmuscle]

Originally posted by sikeveo
hey thanks guyz

you should not have deleted your original post.

it's valuable for other students who are learning or struggling with algorithms.

while you are learning and being corrected, other students are learning too. Do not be ashamed of getting stuff wrong.