2.1. Declaration - JulTob/Ada GitHub Wiki
All variables have to be declared before use. To declare a variable is to set a name (or identificator) for it and a type as follows:
procedure Example is
-- Variables go here in is..begin
Variable : Type; --In the declarative part (before begin)
Const_Variable : constant Type; --For constant parameters
-- Declaration with initialization
Value : Integer := 42
begin
-- ... --
A variable can only have values from it’s type’s set.
The declaration determines the scope.
We also declared the use
of a library so we can use implicit scoping inside the function. Without it we should apply explicit scoping, as follows:
Simple_IO.Get(x);
Simple_IO.Put(sqrt(x));
Get
allows us to read input from console, and Out
to write in console.
Another program Example:
with Sqrt, Simple_IO; --Call to libraries
procedure Print_Root is
use Simple_IO;
X: float;
begin
Put(“Roots of Input number”);
New_Line(2);
loop
Get(X);
exit when X = 0.0;
Put(“ Root of ); Put(X); Put(“ is “);
if X < 0.0 then
Put(“not calculable”);
else
Put(Sqrt(X));
end if;
New_Line;
end loop
New_Line;
Put(“Program finished”);
New_Line;
end Print_Root;