Q(uick)BASIC Function: VAL

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VAL

A string-processing function that returns the numeric value of a string of digits

Worth knowing

Useful and cross-version information about the programming environments of QBasic and QuickBasic.

Syntax

STR$(numeric-expression)
VAL(stringexpression$)

Description/Parameter(s)

numeric-expression	Any numeric expression.
stringexpression$	A string representation of a number.

Example

PRINT "Decimal 65 is represented in hexadecimal as ";
PRINT "&H" + LTRIM$(STR$(41))
PRINT VAL(RIGHT$("Microsoft 1990", 4))

Syntax

VAL(stringexpression)

Description/Parameter(s)

The stringexpression is a sequence of characters that can be interpreted as a numeric value. The VAL function stops reading the string at the first character that it cannot recognize as part of a number. The VAL function also strips leading blanks, tabs, and line feeds from the argument string. For example,

```
VAL("    -33/LP")
```

returns the value -33.

Example

The following program prints the names and addresses of people with specific telephone area codes.

' Example program for the VAL function
'
' ***This part of the program builds a sample data file
'
OPEN "PHONE.DAT" FOR OUTPUT AS #1
CLS
RESTORE
READ FuName$, ACPhone$
I = 0
DO WHILE UCASE$(FuName$) <> "END"
   I = I + 1
   WRITE #1, FuName$, ACPhone$
   READ FuName$, ACPhone$
   IF FuName$ = "END" THEN EXIT DO
LOOP
CLOSE #1
'
   DATA "Bob Hartzell ","206-378-3223"
   DATA "Alice Provan ","213-884-9700"
   DATA "Alex Landow ","213-456-3111"
   DATA "Walt Riley ","503-248-0048"
   DATA "Georgette Gump ","213-222-2222"
   DATA "END",0,0,0,0,0
'
' *** This part of the program demonstrates the VAL function
'
INPUT "Search for which area (206, 213, or 503): ", Targetarea
OPEN "PHONE.DAT" FOR INPUT AS #1
DO WHILE NOT EOF(1)
   INPUT #1, Nm$, Phonenum$
   'VAL reads everything up to the first non-numeric
   'character ("-" in this case).
   Area = VAL(Phonenum$)
   IF Area = Targetarea THEN
      PRINT
      PRINT Nm$;
      PRINT Phonenum$
   END IF
LOOP
CLOSE
KILL "PHONE.DAT"
END

Syntax

VAL(stringexpression$)

Description/Parameter(s)

The argument stringexpression$ is a sequence of characters that can be interpreted as a numeric value.

The VAL function stops reading the string at the first character that it cannot recognize as part of a number. The VAL function also strips blanks, tabs, and line feeds from the argument string. For example, the code below returns the value 1615198

```
VAL("    1615 198th Street")
```

Example

This example uses the VAL function to determine the numeric value of numbers stored as strings. The program prints the names and addresses of people with specific telephone area codes.

'This part of the program builds a sample data file.
OPEN "PHONE.DAT" FOR OUTPUT AS #1
CLS
RESTORE
READ FuName$, ACPhone$
I = 0
DO WHILE UCASE$(FuName$) <> "END"
   I = I + 1
   WRITE #1, FuName$, ACPhone$
   READ FuName$, ACPhone$
   IF FuName$ = "END" THEN EXIT DO
LOOP
CLOSE #1
 
DATA "Bob Hartzell ","206-378-3223"
DATA "Alice Provan ","213-884-9700"
DATA "Alex Landow ","213-456-3111"
DATA "Walt Riley ","503-248-0048"
DATA "Georgette Gump ","213-222-2222"
DATA "END",0,0,0,0,0
 
'This part of the program demonstrates the VAL function.
INPUT "Search for which area (206, 213, or 503): ", Targetarea
OPEN "PHONE.DAT" FOR INPUT AS #1
DO WHILE NOT EOF(1)
   INPUT #1, Nm$, Phonenum$
   'VAL reads everything up to the first non-numeric
   'character ("-" in this case).
   Area = VAL(Phonenum$)
   IF Area = Targetarea THEN
      PRINT
      PRINT Nm$;
      PRINT Phonenum$
   END IF
LOOP
CLOSE
KILL "PHONE.DAT"
END