DAY 036: _STRCMP

[Pete]

So since I wrote about _STRCMP, which came along after I made the abve function, I figured, hey, might as well make use of it to optimize the string math compare routine a bit...

Code: (Select All)

DO
    LINE INPUT "S1: "; string1$
    LINE INPUT "S2: "; string2$
    IF string1$ = "" AND string2$ = "" THEN SYSTEM
    PRINT

    SELECT CASE gl%(string1$, string2$)
        CASE -1
            PRINT string1$; " is smaller than " + string2$
        CASE 0
            PRINT string1$; " is equal to " + string2$
        CASE 1
            PRINT string1$; " is larger than " + string2$
    END SELECT
    PRINT
LOOP

FUNCTION gl% (string1$, string2$)
    s1$ = string1$: s2$ = string2$: neg = 1: d1$ = "": d2$ = ""
    DO ' Falx loop.
        IF LEFT$(string1$, 1) = "-" THEN ' strip off - sign(s). If both are negative, continue.
            IF LEFT$(string2$, 1) <> "-" THEN gl% = -1: EXIT DO
            s1$ = MID$(s1$, 2)
            neg = -1
        END IF
        IF LEFT$(string2$, 1) = "-" THEN
            IF LEFT$(string1$, 1) <> "-" THEN gl% = 1: EXIT DO
            s2$ = MID$(s2$, 2)
            neg = -1
        END IF

        s1 = INSTR(s1$, "."): s2 = INSTR(s2$, ".") ' ID if decimal(s).
        IF s1 THEN x1$ = MID$(s1$, 1, s1 - 1): d1$ = MID$(s1$, s1 + 1) ELSE x1$ = s1$ ' strip off decimal(s).
        IF s2 THEN x2$ = MID$(s2$, 1, s2 - 1): d2$ = MID$(s2$, s2 + 1) ELSE x2$ = s2$

        IF LEN(x1$) > LEN(x2$) THEN x2$ = STRING$(LEN(x1$) - LEN(x2$), "0") + x2$
        IF LEN(x2$) > LEN(x1$) THEN x1$ = STRING$(LEN(x2$) - LEN(x1$), "0") + x1$

        IF LEN(d1$) > LEN(d2$) THEN d2$ = d2$ + STRING$(LEN(d1$) - LEN(d2$), "0")
        IF LEN(d2$) > LEN(d1$) THEN d1$ = d1$ + STRING$(LEN(d2$) - LEN(d1$), "0")

        x1$ = x1$ + "." + d1$: x2$ = x2$ + "." + d2$
        gl% = _STRCMP(x1$, x2$) * neg
        EXIT DO
    LOOP
END FUNCTION

I'm not 100% sure if it's bullet proof yet, so if anyone can find a flaw, please let me know.

Pete