-- Ada function-calling demonstration program.
-- Ada has nested block and function scope and automatic for loop scope with Text_IO; use Text_IO; -- This gets the IO facility.
-- Ada
with Gnat.Io; use Gnat.Io;
procedure hello is -- Main, but no special name is needed.
    pt1 : Integer := 4; 
    pt2 : Integer := 5;

    procedure swap( a : in out Integer;
                             b : in out Integer ) is
        c : Integer; 
    begin
        c := b; 
        b := a; 
        a := c;
    end swap;
    
begin
    Put( "Before calling swap pt1 is " ); 
    Put( pt1 );
    Put( ", pt2 is " );
    Put( pt2 );
    Put_Line( "" );
    swap( pt1, pt2 );
    Put( "Before calling swap pt1 is " ); 
    Put( pt1 );
    Put( ", pt2 is " );
    Put( pt2 );
    Put_Line( "" ); 
    swap( pt1, pt2 );
end hello;