Qbasic - trying to call a sub, but i get a message that says "Expected CALL, subname, (...)"

Question

Here is the code, it takes 5 names and alphabetizes them. I have a sub that sorts the names but apparently i'm not calling it in the correct way.

DIM i AS INTEGER
DIM q AS INTEGER
DIM a AS STRING
DIM n(5) AS STRING
DIM z AS INTEGER
DIM x AS INTEGER
DIM y AS INTEGER
DIM g AS INTEGER

start:
CLS

FOR i = 1 TO 5
    INPUT "Name:", n(i) 'receiving 5 names
NEXT i

call Sort()                                **This is the line with the error**

PRINT "Names in Alphabetical Order:"
FOR i = 1 TO 5
    PRINT n(i)
NEXT i
INPUT "Again(y, n)", a
IF LCASE$(a) = "y" THEN GOTO start
IF LCASE$(a) <> "y" THEN STOP

'end of main program

SUB Sort (`enter code here`)
    FOR i = 1 TO 5
        FOR q = 1 TO 4
        IF LCASE$(n(q)) > LCASE$(n(q + 1)) THEN SWAP n(q), n(q + 1)
        IF LCASE$(n(q)) = LCASE$(n(q + 1)) THEN

            z = LEN(n(q))
            x = LEN(n(q + 1))
            IF z > x THEN g = x
            IF z < x THEN g = z

            IF z > 1 AND x > 1 THEN
                FOR y = 2 TO g
                    IF LCASE$(MID$(n(q), y, 1)) > LCASE$(MID$(n(q + 1), y, 1)) THEN
                        SWAP n(q), n(q + 1)
                        END
                    END IF
                    IF y = g THEN SWAP n(q), n(q + 1)
                NEXT y
            END IF
        END IF
    NEXT q
NEXT i

END SUB

I have tried putting a parameter in the sub, "SUB Sort(n())", the array that has the names in it, but it said incorrect array type.

score 2 · Answer 1 · answered Aug 26 '18 at 17:49

Your problem is the fact that you typed SORT() when there are no arguments.

Invoking a SUB or FUNCTION with correct syntax can be a bit strange in QB at first, and the syntax for the CALL keyword makes things even more confusing:

' No arguments means you MUST NOT include the () afterward.
CALL SubNameE

' One non-array argument: n
CALL SubNameX(n)

' Two non-array arguments: a, b
CALL SubNameY(a, b)

' An array argument and a non-array argument: arr(), v
CALL SubNameZ(arr(), v)

Notice how arrays are passed to SUB and FUNCTION procedures using name(). The interpreter probably gets confused when you write call SORT() as SORT() is the syntax for an array, not a SUB/FUNCTION call with no arguments.

You can also write the above lines of code without the CALL keyword if that helps you:

' No arguments means only the procedure name is listed.
SubNameE

' One non-array argument: n
SubNameX n

' Two non-array arguments: a, b
SubNameY a, b

' An array argument and a non-array argument: arr(), v
SubNameZ arr(), v

Note that for a SUB or FUNCTION to accept an array argument, it must have them declared, like this:

SUB SORT (n() AS STRING)
' or if you wanted to use a type suffix
SUB SORT (n$())

eoredson · Answer 2 · 2018-08-27T01:18:27.450

Here is an easy way to pass an array to a sort subroutine in qb64:

DIM n(5) AS STRING
n(1) = "zachary smith"
n(2) = "xerox johnson"
n(3) = "yackle jones"
n(4) = "arnold aglet"
n(5) = "beth anderson"
CALL Sort(n())
FOR i = 1 TO 5: PRINT n(i): NEXT
END
SUB Sort (n() AS STRING)
FOR i = 1 TO 5
    FOR j = i + 1 TO 5
        IF n(i) > n(j) THEN SWAP n(i), n(j)
    NEXT
NEXT
END SUB

Here is an easier way to call a sort subroutine without specifying a parameter:

DIM SHARED n(5) AS STRING
n(1) = "zachary smith"
n(2) = "xerox johnson"
n(3) = "yackle jones"
n(4) = "arnold aglet"
n(5) = "beth anderson"
CALL Sort
FOR i = 1 TO 5: PRINT n(i): NEXT
END
SUB Sort
FOR i = 1 TO 5
    FOR j = i + 1 TO 5
        IF n(i) > n(j) THEN SWAP n(i), n(j)
    NEXT
NEXT
END SUB

Qbasic - trying to call a sub, but i get a message that says "Expected CALL, subname, (...)"

2 Answers2