# Uses Crt Graph Type tChain tSection tSection record shortint shortint

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231``` ```Uses Crt, Graph; Type tChain = ^tSection; tSection = record x : shortint; y : shortint; next : tChain; end; Const arrowSymbols : set of char = [#80,#72,#77,#75]; Var gd, gm : integer; pMark : pointer; First, Current, Last : tChain; i : byte; ch1, ch2 : char; {----------------------------------------------------------------------------} Procedure CreateChain; const count : boolean = FALSE; begin if NOT (count) then begin new(First); Current := First; count := TRUE; end else begin new(Current^.next); Current := Current^.next; end; Current^.next := nil; Last := Current; end; {----------------------------------------------------------------------------} Procedure PosSnake; begin setcolor(2); for i := 0 to 9 do begin CreateChain; Current^.x := i; Current^.y := 0; circle(Current^.x*20+10,Current^.y*20+10,10); end; end; {----------------------------------------------------------------------------} Procedure MoveChain; begin Current := First; while Current <> Last do begin Current^.x := (Current^.next)^.x; Current^.y := (Current^.next)^.y; Current := Current^.next; end; end; {----------------------------------------------------------------------------} Procedure GameOver; begin cleardevice; setcolor(1); outtextxy(275,240,'Game Over!!!'); ch2 := #27; delay(65535); end; {----------------------------------------------------------------------------} Procedure BorderTest; begin if Last^.x = -1 then GameOver; if Last^.y = -1 then GameOver; if Last^.x = 32 then GameOver; if Last^.y = 24 then GameOver; end; {----------------------------------------------------------------------------} Procedure SelfDestroyTest; begin Current := First; while Current <> Last do begin if (Current^.x = Last^.x) AND (Current^.y = Last^.y) then GameOver; Current := Current^.next; end; end; {----------------------------------------------------------------------------} Begin gd := DETECT; initgraph(gd,gm,''); cleardevice; mark(pMark); PosSnake; ch2 := #77; repeat delay(30000); if keypressed then ch2 := readkey; if ch2 = #0 then ch2 := readkey; if ch2 in arrowSymbols then ch1 := ch2; setcolor(0); circle(First^.x*20+10,First^.y*20+10,10); MoveChain; case ch1 of #80 : inc(Last^.y); #72 : dec(Last^.y); #77 : inc(Last^.x); #75 : dec(Last^.x); end; setcolor(2); circle(Last^.x*20+10,Last^.y*20+10,10); BorderTest; SelfDestroyTest; until ch2 = #27; release(pMark); closegraph; End. ```