program test_const_string;


function astring(s :string) : string;

begin
  astring:='Test string'+s;
end;

procedure testvar(var s : string);
begin
  writeln('testvar s is "',s,'"');
end;

procedure testconst(const s : string);
begin
  writeln('testconst s is "',s,'"');
end;

procedure testvalue(s : string);
begin
  writeln('testvalue s is "',s,'"');
end;

const
  s : string = 'test';
  
begin
  testvalue(astring('e'));
  testconst(astring(s));
  testconst(astring(45));
  {testvar(astring);refused a compile time }
end.