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I am trying to pass my array of integers called "Arr" to a function "collect". inside of collect, I am collecting an int from the user. once the user puts in 100 ints or gives a value of 0 or a negative number the array will stop collecting. What am I doing wrong?

with Ada.Text_IO, Ada.Integer_Text_IO; use Ada.Text_IO; procedure helloworld is procedure PrintHelloWorld is begin Put_Line ("Enter Integers, up to 100 individual ints."); end PrintHelloWorld; function collect (A : array) return array is A: array (1 .. 100) of integer; begin Ada.Text_IO.Put ("Enter an integer: "); Ada.Integer_Text_IO.Get(I); Ada.Text_IO.Put_Line (Integer'Image(I)); if I > 0 then A(i) := I; end if; while I > 0 loop Ada.Text_IO.Put ("Enter an integer: "); Ada.Integer_Text_IO.Get(I); Ada.Text_IO.Put_Line (Integer'Image(I)); if I > 0 then A(i) := I; end if; end loop; return A; end collect; procedure printArr is begin for j in Arr'range loop Ada.Text_IO.Put_Line(Integer'Image(Arr(j))); end loop; end printArr; Arr: array (1 .. 100) of integer; Arr := (others => 0); I: Integer; begin Put_Line ("Hello World!"); PrintHelloWorld; Arr := collect(Arr); printArr; end helloworld;

Terminal errors:

gnatmake helloworld.adb x86_64-linux-gnu-gcc-8 -c helloworld.adb helloworld.adb:13:26: anonymous array definition not allowed here helloworld.adb:13:46: reserved word "is" cannot be used as identifier helloworld.adb:15:08: missing ")" gnatmake: "helloworld.adb" compilation error
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    You are probably getting messages from the compiler that the function doesn't return anything. Well, it doesn't. Furthermore you have a global variable, a formal parameter to the function, and a local variable, all with the same name. Guess which one is visible... Also, see stackoverflow.com/questions/61568595/… : presumably one of your classmates working on the same assignment? Commented May 4, 2020 at 19:46
  • function collect (A : array) return array won’t even compile. You need to declare an array type. Commented May 4, 2020 at 20:01
  • @BrianDrummond Thank you for the response. I updated my code along with the errors from the terminal. Commented May 4, 2020 at 20:01
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    @SimonWright so would something like this be an array type? type Vector is array (Integer range <>) of Integer; Commented May 4, 2020 at 20:16
  • 1) If you're passing an array IN to collect : make it a procedure with an In Out mode parameter, (No need for two arrays : simpler.) 2) Also : initialise the array in its declaration, e.g. by := (others => 0) so it doesn't contain garbage. 3) Don't use magic numbers when looping over the array (you have beautifully illustrated why!) : use for i in Arr'range instead. Commented May 4, 2020 at 20:29

2 Answers 2

Reset to default
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It appears that your thinking is stuck somewhere between C/C++/Java syntax and Ada. Try the following example.

with Ada.Text_IO; use Ada.Text_IO; with Ada.Integer_Text_IO; use Ada.Integer_Text_IO; procedure Main is type Data_Array is array(Positive range <>) of Integer; function Collect return Data_Array is Count : Natural := 0; begin Put_Line("Enter the number of data values you will input"); Get(Count); declare Nums : Data_Array(1..Count); begin Put_Line("Enter" & Count'Image &" values"); for Value of Nums loop Get(Value); end loop; return Nums; end; end Collect; procedure Print(Item : in Data_Array) is begin Put_Line("Output of array values:"); for Value of Item loop Put_Line(Value'Image); end loop; end Print; begin Print(Collect); end Main;

The procedure Print takes a parameter of type Data_Array, which is provided by the return value of the function Collect. The function collect only returns an array of exactly the size needed. The procedure Print takes an array of whatever size you send it and prints the contents of that array.

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The definition of the array inside of function collect (in the original code) may come from the Fortran 77 syntax.
1

Here you are; I've also made it so you can add negative numbers.
(If that's not what you want, change the element type of Vector to Natural or Positive as desired.)
Note that the --' comments are a workaround to the buggy syntax highlighter.

Pragma Ada_2012; Pragma Assertion_Policy( Ignore ); Pragma Restrictions( No_Implementation_Aspect_Specifications ); Pragma Restrictions( No_Implementation_Pragmas ); With Ada.Strings.Equal_Case_Insensitive, Ada.Text_IO.Text_Streams; Procedure Example is -- Counting and indexing types. Type Count is range 0..100; Subtype Index is Count range Count'Succ(Count'First)..Count'Last; --' -- Array-type; its range is constrained by Index. Type Vector is Array(Index range <>) of Integer; -- Here we build the input-vector. Function Get_Input return Vector is -- Here we get user-input; we pass our working-set as a parameter so -- that it can be built in-place; this also ensures that we only ever -- generate a result of the appropriate length. Function Get_Working( Working : Vector:= (2..1 => <>) ) return Vector is Function "="(Left, Right : String) Return Boolean renames Ada.Strings.Equal_Case_Insensitive; Begin -- We never try to add to a full array. if Working'Length = Index'Last then return Working; end if; -- We get an integer, or are finished. loop Ada.Text_IO.Put( "Enter an integer or type 'Done': " ); READ_INPUT: Declare User_Input : Constant String:= Ada.Text_IO.Get_Line; Begin return Get_Working( Working & Integer'Value(User_Input) ); --' Exception when Constraint_Error => if User_Input = "Done" then return Working; end if; End READ_INPUT; end loop; End Get_Working; Begin Return Get_Working; End Get_Input; Procedure Print( Object : Vector ) is Begin Ada.Text_IO.Put( '[' ); for Index in Object'Range loop --' Ada.Text_IO.Put( Integer'Image(Object(Index)) ); --' if Index /= Object'Last then --' Ada.Text_IO.Put(','); end if; end loop; Ada.Text_IO.Put( ']' ); End Print; Begin declare V : constant Vector:= Get_Input; begin Print( V ); Ada.Text_IO.New_Line( 2 ); end; Ada.Text_IO.Put_Line( "Done." ); End Example;

Example run:
Enter an integer or type 'Done': 21
Enter an integer or type 'Done': 4
Enter an integer or type 'Done': 18
Enter an integer or type 'Done': DONE
[ 21, 4, 18]

Done.

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