1 program Project21;
 2 
 3  {$APPTYPE CONSOLE}
 4 
 5  uses
 6   SysUtils;
 7 
 8  procedure Draw(Size:Integer);
 9  var
10   Arr:Array of Array of Integer;
11   Flag:(GoRight,GoButtom,GoLeft,GoTop);
12   X,Y,N,Step,Rang:Integer;
13   procedure Output;
14   begin
15     Inc(N);
16     Arr[Y,X]:=N;
17     Dec(Step);
18   end;
19 begin
20   N:=0; X:=0; Y:=0;
21   Rang:=Size-1; Step:=Rang;
22   SetLength(Arr,Size,Size);
23   while N<Size*Size do begin
24     case Flag of
25       GoRight:
26       begin
27         if Step=0 then begin
28           Step:=Rang;
29           Flag:=GoButtom;
30         end else begin
31           Output;
32           Inc(X);
33         end;
34       end;
35       GoButtom:
36       begin
37         if Step=0 then begin
38           Step:=Rang;
39           Flag:=GoLeft;
40         end else begin
41           Output;
42           Inc(Y);
43         end;
44       end;
45       GoLeft:
46       begin
47         if Step=0 then begin
48           Step:=Rang;
49           Flag:=GoTop;
50         end else begin
51           Output;
52           Dec(X);
53         end;
54       end;
55       GoTop:
56       begin
57         if Step=0 then begin
58           Dec(Rang,2);
59           Step:=Rang;
60           Flag:=GoRight;
61           Inc(X);
62           Inc(Y);
63           if Rang<=0 then begin
64             Output;
65             Break;
66           end;
67         end else begin
68           Output;
69           Dec(Y);
70         end;
71       end;
72     end;
73   end;
74   for Y := 0 to Size-1 do begin
75     for X := 0 to Size-1 do
76       Write(Format('%4d',[Arr[Y,X]]));
77     Writeln('');
78   end;
79 end;
80 
81 var
82   Size:String;
83 label
84   Start;
85 begin
86   try
87     Start:
88     Write('输入阵列的规模:');
89     Readln(Size);
90     Draw(StrToIntDef(Size,0));
91     goto Start;
92   except
93     on E: Exception do
94       Writeln(E.ClassName, ': ', E.Message);
95   end;
96 end.