Radio Shack TRS-80 Model 100 Basic Manual page 158

70 FOR T = 1 TO 30
80 SOUND 7000,1
80 A$=CHR$(145+3*RND(1»
1006$=CHR$(145+3*RND(1»
110 C$=CHR$(145+3*RND(1»
120 PRINT@ 137,A$;
130 PRINT@ 138,6$;
140 PRINl@ 141,C$;
150 NEXT T
180 IF A$=B$ AND 6$=C$ GOTO 200
170 PRINT@ 240,"Press ENTER"
180 A$=INKEY$ : IF A$=""GOTO 180
180 PRINT@ 240, " " : GOTO 20
200 FOR J=l TO 4
210 PRINT@ 217,
"1-1
I N";
220 FOR 1=1800 TO 800 STEP -50
230 SOUND 1,2 : NEXT I
240 PR I NT@ 217, " " ;
250 FOR K=l TO 100 : NEXT K
280 NEXT J : GOlO 170
Execute the program.
A slot machine will appear on the display with three characters appearing at random in
the windows. After a few seconds the characters will stop changing. A win occurs if
all three characters are the same. The beeping sound is used to help simulate motion
in the slot machine. If you don't win, you can press
CEtITE:ID
to play again. When a
win occurs a siren will sound and "W I N" will flash on the slot machine.
Line 18 The time is used to initialize the sequence of random numbers.
Line
28
This statement clears the display.
Line 38 The outline of the slot machine is drawn as a box using the LINE statement.
Lines 40-60 The three windows are drawn as boxes using the LINE statement.
Line 78 A FOR / NEXT loop is used to control the duration of the spinning of the
slot machine wheels. The upper limit of 30 was determined by trial and error. A larger
value would increase the duration and a smaller value decrease it.
Line 88 A brief tone is generated to suggest rotation of the wheel. Again the
parameters were chosen by trial and error to create a reasonable sound.
Lines
98-118
The characters with ASCII values,
145, 146
and
147
were chosen to be
the display characters because they have contiguous ASCII values and they look
interesting. These three characters are generated at random with the CHR$ function
CHR$(145 + 3 * RND(l»
Since the argument of the CHR$ is truncated to an integer value, this function will
return one of the three characters
152