0 REM << RR20-2 >>
1 REM
2 REM  --  BIRTHDAY CALC  --
3 REM    RUPERT REPORT #20
4 REM
10 REM - CALCULATE THE PROBABILITY
11 REM   THAT FOR A GROUP OF NP PEOPLE
12 REM   TWO OR MORE OF THEM WERE BORN
13 REM   ON THE SAME DAY OF THE YEAR
14 REM
20 PRINT CHR$(147):POKE53280,7:POKE53281,9:POKE646,7
30 PRINT "HOW MANY PEOPLE ARE IN THE ROOM":PRINT"(ENTER 0 FOR COMPLETE LIST)"
40 INPUT NP
50 IF NP<=0 OR INT(NP)<>NP THEN 200
60 PF=1    :REM PROBABILITY OF FAILURE
70 FOR Q=1 TO NP
80 PF=(367-Q)*PF/366 : NEXT
90 PS=1-PF :REM PROBABILITY OF SUCCESS
100 PRINT
110 PRINT"IN A GROUP OF" NP "PEOPLE,"
120 PRINT"THERE IS A" PS*100 "PERCENT"
130 PRINT"PROBABILITY THAT TWO OR MORE"
140 PRINT"PEOPLE HAVE THE SAME BIRTHDAY"
150 PRINT
160 GOTO 30
200 PF=1
210 FOR NP=1 TO 366
220 PF=PF*(367-NP)/366
230 PRINT "# PEOPLE ="NP;
240 PRINT "   % PROB. =" (1-PF)*100
245 REM  COUNT # OF LINES LISTED (NL)
250 NL=NL+1 : IF NL<20 THEN 290
260 NL=0
270 PRINT "PRESS ANY KEY FOR MORE..."
280 GET X$:IF X$="" THEN 280
290 NEXT