1. Computer Science 2
Tally Arrays
2/4/2016

2. Learning Objectives
Students will be able to use arrays to keep track of votes for an election

3. Dry run practice. tot:=0; for count: = 1 to 3 do num[count]: = 0 ;
Begin
tot:= count mod 3 + 1;
inc(num[tot]);
End;
For count:= 1 to 3 do
writeln(num[count]);

4. Tally Array notes Types of uses for an array
General: Storing lots of stuff
Tallying: Storing votes for lots of events
Sorting: Putting stuff in order

5. Election time
We’ll be writing the code to run a small election between thee candidates. It will get votes and show the results of the election.
Can this be done without using arrays?

6. Getting Ready to Code
Hands on
Pseudo Code
Dry Run
Code

7. while (vote<>4) do begin case Vote of 1:Cand1:=Cand1+1;
end;
Writeln(‘Please vote for’);
Writeln(‘1-Wilma’);
writeln(‘2-Fred’);
writeln(‘3-Barney’);
writeln(‘4-quit’);
readln(Vote);
end; {Of the while}
writeln(‘Wilma has ‘,Cand1);
writeln(‘Fred has ‘,Cand2);
writeln(‘Barney has ‘,Cand3);
end.
Program NoArrayElection;
var
Cand1, Cand2, Cand3:integer;
Vote:integer;
begin
Cand1:=0;{These hold the number of}
Cand2:=0;{ votes for the candidates}
Cand3:=0;
Writeln(‘Please vote for’);
Writeln(‘1-Wilma’);
writeln(‘2-Fred’);
writeln(‘3-Barney’);
writeln(‘4-quit’);
readln(Vote);
What if there are more candidates?
Translating this to using arrays

8. We need to save the votes for the four candidates.
What type of an array would you use?
Declare it
TYPE
VAR

9. Program Options
Write a program that will roll a pair of six-sided dice 1000 times and count and display how often each roll occurs. Also show which roll occurs the most often and which occurs the least often.
Push: Compare the results to what should happen statistically.
Push: Display the results in a graph.
Write the program for the election as in the warm ups and tell the winner of the election.
Push: Let the use choose the names of the candidates
Push: Store the names of the candidates in another array.
Push: Let the user pick the names of the candidates, and how many candidates (up to 10)
Write a program to keep track of scoring during a basketball game.
Use the player number to find the address in the array (To keep it simple, just use player numbers 1..10). And the person can score 1, 2, or 3 points on each basket. Show the results (the points scored by each player at the end.)
Push: Keep track of the names of the players also
Push: Show the name of the player that scored the most points.