Snake

1057 IF SCREEN<=8 THEN IF TIME THEN IF B=U THEN GO TO 4 CLS LET LIUES=LIUES-1 CR 8 INK 7 BRIGHT 1 GO TO a s e 3 GO TO a s e 4 BEEP . 3 , 7

650 INPUT "¿CÓMO TE LLAMAS?"$; 660 GO TO 10 700 PRINT AT a,b;CHR$(148+C) 710 FOR n=30 TO 1 STEP -1: BEEP: NEXT n 1000 BRIGHT 1:PAPER 6:INK 2:ORDER 6:CLS 1020 PRINT "SNAKE" AT 5,8

1057 IF SCREEN<=8 THEN IF TIME=U THEN IF B=U THEN GO TO 4 CLS LET LIUES=LIUES-1 CR 8 INK 7 BRIGHT 1 CLS GO TO a s e 3 GO TO a s e 4 BEEP . 3 , 7

—«P» hacia DERECHA.
—«O» hacia IZQUIERDA.
—«Q» hacia ARRIBA.
—«A» hacia ABAJO.

You get an example program with the package. Snake, which is surprisingly small.

POKEP1+>.:-224tY,HD

5 POKE53280,121POKE53281,12

The scroll-left machine-code program is used to store the position to reset the snake's tail and will change it each time you move.

PCLEAR8
INPUT A*
POKE 50,A
INPUT TT
POKE 70,TT
PRINT TT
POKE 80,LEN(A*)
STEP 2
SUM=SUM+C
POKE N+Z,C
ZZ+1

To load the program create Rem lines 1-10, each 43 characters long. Then Poke 16511,230 and Poke 16512, 1 to make one long line.

POKE10+X+Y*22,58:POKE10+C0+X+Y*22,2

51 line number.100
10 FOR i=30000 TO 34040 STEP 15
15 tot = 0
20 READ A$
330 DATA 803A4E76E0IT803A,80
340 DATA

POKE36581,HEXTI

1500 FOR n=22560 TO 22591: POKE n,16: POKE n+640,16: NEXT n
1510 FOR n=22592 TO 22592+32 STEP 32: POKE n,16: POKE n+31,16: NEXT n

Line 10 sets the border, paper and ink colours and clears the screen. The high score and score are set to zero by Lines 20 and 100. Line 30 DIMensions array s, which will be used to store the screen coordinates of the snake. Initially, the snake will occupy (10,14), (11,14) and (12,14). Lines 110 to 130 place the coordinates in the first three elements of the array. Line 135 calls the 'setting up the screen' subroutine, starting at Line 1500. The border is drawn by POKEing into the attribute file—Line 1500 draws the lines at the top and bottom of the screen, and Line 1510 draws the borders at the sides. Line 1520 sets up the score and high score. Line 140 sets up the head and tail pointers to array s. They tell the machine that the tail coordinates are stored in the first pair of array elements, and the head coordinates are stored in the third pair of elements. As the snake moves, the two pointers are adjusted and the new head position is slotted into the array. The vectors xv yv, keep track of the direction the snake is heading. Both xv and yv can take three values: 0 means the snake isn't heading in that direction; 1 means the snake is heading down or right; and —1 means the snake is heading up or right. Line 145, then, makes the snake move up the screen at the start of the game. The snake, consisting of three hashes, is PR INTed by Line 150. The current head position is given by x and y and these are used to detect collisions. Line 160 has the head positioned at 14,12. Line 165 sets the value of the displayed number, p, to zero. The INKEY$ subroutine, starting at Line 1000, is called by Line 170. 0 and A move the snake up and down, and 0 and P move it left and right. Pressing the keys change xv and yv, and Line 1050

POKEd by Line 350

Line 2000 alone

RECOVERY+D

SAVE "SNAKE TRAP"

V P0 K E 256,120: S(0)=6275