TI99 Environment

POS

Syntax

integer-variable = POS(string1,string2,position)

Description

The POS function returns the position of the first occurrence of string2 in a string1. The search begins at the position specified by position. If no match is found, the function returns a value of zero. This function is the TI99 equivalent of INSTR.

Example Code

` ROCK, PAPER, SCISSORS
 RANDOMIZE HITIMER()
 GAMEOVER$ = "N" : PLAYERWINS = 0 : COMPUTERWINS = 0 : CRPS$="RPS"
 DIM ARPS$(3)
 ARPS$(1)="ROCK"
 ARPS$(2)="PAPER"
 ARPS$(3)="SCISSORS"
 REPEAT
    CALL_CLEAR()
    WIN = -1
    DISPLAY_AT(4,1,"ROCK, PAPER, SCISSORS",0)
    DISPLAY_AT(6,1,"R=ROCK, P=PAPER, S=SCISSORS",0)
    PLAYER$=""
    WHILE PLAYER$ = ""
      PLAYER$ = FAST UPPER$(FAST LEFT$(ACCEPT_AT(8,1,"","TYPE R,P, OR S:",0),1))
      PCHOICE = POS(CRPS$,PLAYER$,1)
      IF PCHOICE = 0 THEN PLAYER$ = ""
    ENDWHILE
    CALL_CLEAR()
    PCHOICE$ = ARPS$(PCHOICE)
    COMPUTER$ = MID$(CRPS$,RND(2)+ 1,1)
    CCHOICE$ = ARPS$(POS(CRPS$,COMPUTER$,1))
    DISPLAY_AT(4,1,"YOU CHOSE:" + PCHOICE$,0)
    DISPLAY_AT(6,1,"COMPUTER CHOSE:" + CCHOICE$,0)
    IF PLAYER$ = "R" AND COMPUTER$ = "S" THEN WIN = 1
    IF PLAYER$ = "P" AND COMPUTER$ = "R" THEN WIN = 1
    IF PLAYER$ = "S" AND COMPUTER$ = "P" THEN WIN = 1
    IF PLAYER$ = "R" AND COMPUTER$ = "P" THEN WIN = 0
    IF PLAYER$ = "P" AND COMPUTER$ = "S" THEN WIN = 0
    IF PLAYER$ = "S" AND COMPUTER$ = "R" THEN WIN = 0
    IF WIN = 1 
      DISPLAY_AT(10,1,PCHOICE$+ " BEATS " + CCHOICE$,0)
      DISPLAY_AT(11,1,"YOU WIN",0)      
      INC PLAYERWINS
    ENDIF
    IF WIN = 0
      DISPLAY_AT(10,1,CCHOICE$+ " BEATS " + PCHOICE$,0)
      DISPLAY_AT(11,1,"COMPUTER WINS",0)      
      INC COMPUTERWINS
    ENDIF
    IF WIN = -1
      DISPLAY_AT(10,1,"IT'S A TIE",0)      
    ENDIF
    DISPLAY_AT(14,1,"SCORE:",0)
    DISPLAY_AT(15,1,"YOU:" + STR$(PLAYERWINS),0)
    DISPLAY_AT(16,1,"COMPUTER:" + STR$(COMPUTERWINS),0)
    DISPLAY_AT(18,1,"ONE MORE? (Y/N)",0)
    ONEMORE$ = TIWAITYN()
    IF ONEMORE$ = "N" THEN GAMEOVER$ = "Y"
 UNTIL GAMEOVER$ = "Y"

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