Stuck on an Ada Program - Stuck on Input - ada

Question

I have a pretty simple Ada project on my hands. The task is to take a collection of a "voter's" votes and compare it to each "candidate's" score and determine which candidate best matches the voter.
The input looks like this, followed by the output that should be put out:
Input:
0 0 0 1 1 1 -1 -1 -1 1
7
A
1 1 1 1 1 1 1 1 1 1
B
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1
C
1 -1 1 -1 1 -1 1 -1 1 -1
D
1 0 1 0 1 0 1 0 1 0
E
0 -1 0 -1 0 -1 0 -1 0 -1
F
1 1 1 1 0 0 0 0 0 0
G
0 0 0 1 -1 0 0 -1 1 1
Output:
A
F
G
So far, I have a procedure that will take the votes of each candidate and compare them to the votes of the voter. I know what I need to do as I have done it before in Java, but I am not sure how I should take the input in Ada. Here is what I have so far.
with Ada.Text_IO, Ada.Integer_Text_IO;
use Ada.Text_IO, Ada.Integer_Text_IO;
procedure Candidates is
-- take an array of candidates and determine which candidate best matches
-- the user's votes, then return those candidates
Number_Of_Candidates: Integer;
subtype VoterArray_Index is Integer range 1..10;
subtype CandidatesArray_Index is Integer range 1..Number_Of_Candidates;
type VoterArray is array(VoterArray_Index) of Integer;
type CandidatesArray is array(Character range 'A' .. 'Z') of array;
type Best_CandidatesArray is array(CandidatesArray_Index) of array;
Voter: VoterArray;
Candidates: CandidatesArray;
Best_Candidates: Best_CandidatesArray;
function Get_Input() is
-- get the input and put it into the correct arrays
Current_Line : string;
begin
Get(Current_Line);
function Get_Best_Score(CandidatesArray: in out CandidatesArray) is
-- go through the arrays and find the best score
SameAnswers: Integer;
DifferentAnswers: Integer;
BestScore: Integer;
subtype CandidateArray is array(VoterArray_Index) of Integer;
Candidate: CandidateArray;
begin
for I in CandidatesArray_Index loop
Candidate := Candidates(I);
for J in VoterArray_Index loop
if Candidate(J) /= 0 and Voter(J) /= 0 then
if Candidate(J) /= Voter(J) then
DifferentAnswers := DifferentAnswers + 1
else
SameAnswers := SameAnswers + 1
end if;
end if;
end loop;
if SameAnswers - DifferentAnswers >= BestScore then
Best_Candidates(I) := Candidate;
end if;
SameAnswers := 0;
DifferentAnswers := 0;
end loop;
end Get_Best_Score;
As you can see, I'm not sure how to take the numbers and put them into an array. If you have any suggestions or a different way I should go about things, I'm all ears.
Thanks in advance.

Answer 1

You could use streams in order to read the data in:
Integer'Read( STREAM_HANDLE, VARIABLE )
Another option is reading the values via Get for each element of your array, I'd recommend a helper-function in case you need to tweak the procedure for handling format changes:
Function Get_Vote ( File : File_Type ) Return Integer is
begin
Return Result : Integer do
Integer_IO.Get(
File => File,
Item => Result
);
End return;
end Read_Votes;
and
For Index in VOTE_ARRAY'range loop
VOTE_ARRAY( Index ) := Get_Vote( INPUT_FILE );
End loop;

Answer 2

Because the number of rows is given in the file, a constrained array has to be large enough to hold all possible elements. Instead, you can declare an unconstrained array:
subtype Voter_Index is Positive range 1 .. 10;
type Voter_Array is array(Voter_Index) of Integer;
type Candidate_Array is array(Character range <>) of Voter_Array;
Later, when you know the actual count, you can allocate only the space actually required for the array. This declaration puts Candidates on the stack in a nested scope:
Number_Of_Candidates := ...;
declare
Candidates : Candidate_Array(
'A' .. Character'Val(Character'Pos('A') + Number_Of_Candidates));
begin
...
end;
Alternatively, you can allocate space on the heap:
type Candidate_Array_Ptr is access Candidate_Array;
Candidates: Candidate_Array_Ptr;
begin
Number_Of_Candidates := ...;
Candidates := new Candidate_Array(
'A' .. Character'Val(Character'Pos('A') + Number_Of_Candidates));
end;
In either case, you can access the array elements as required:
for i in Candidates'Range loop
for j in Voter_Array'Range loop
Ada.Integer_Text_IO.put(Candidates(i)(j), 5);
end loop;
Ada.Text_IO.New_Line;
end loop;
Addendum: This approach assumes that candidate names are consecutive Characters. As an alternative, consider an array of Candidate_Record, where each Name is read from the file:
type Candidate_Record is
record
Name : Character;
Votes : Voter_Array;
end record;
type Candidate_Array is array(Positive range <>) of Candidate_Record;
Candidates : Candidate_Array(1 .. Number_Of_Candidates);
for i in Candidates'Range loop
Ada.Text_IO.Put(Candidates(i).Name & ':');
for j in Voter_Array'Range loop
Ada.Integer_Text_IO.Put(Candidates(i).Votes(j), 5);
end loop;
Ada.Text_IO.New_Line;
end loop;