t.txt

原创！PL0词法分析程序的源码！能够实现用PL0语言进行词法及语法分析！

var a,b,c,d,e;
procedure p;
  begin
     c:=1/a
  end;

procedure q;
  begin
     d:=1/b
  end;

procedure r;
  begin
     e:=2/(c+d)
  end;

  begin
    read(a);
    read(b);
    while a#0 do
       begin
          call p;
          call q;
          call r;
          write(e);
          read(a);
          read(b)
       end
end.