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Executes a set of commands within a conditional loop.
DO WHILE lExpression
Commands
[LOOP]
[EXIT]
ENDDO |
Parameters
- lExpression
- Specifies a logical expression whose value determines whether the commands between DO WHILE and ENDDO are executed. As long as lExpression evaluates to true (.T.), the set of commands are executed.
- Commands
- Specifies the set of Visual FoxPro commands to be executed as long as lExpression evaluates to true (.T.).
- LOOP
- Returns program control directly back to DO WHILE. LOOP can be placed anywhere between DO WHILE and ENDDO.
- EXIT
- Transfers program control from within the DO WHILE loop to the first command following ENDDO. EXIT can be placed anywhere between DO WHILE and ENDDO.
Remarks
Commands between DO WHILE and ENDDO are executed for as long as the logical expression lExpression remains true (.T.). Each DO WHILE statement must have a corresponding ENDDO statement.
Comments can be placed after DO WHILE and ENDDO on the same line. The comments are ignored during program compilation and execution.
Example
In the following example, the number of products in stock priced over $20 is totaled in the DO WHILE loop until the end of the file (EOF) is encountered. The DO WHILE loop is exited and the total is displayed.
| В |  Copy Code |
|---|---|
CLOSE DATABASES
OPEN DATABASE (HOME(2) + 'Data\testdata')
USE products && Opens Products table
SET TALK OFF
gnStockTot = 0
DO WHILE .T. && Begins loop
IF EOF( )
EXIT
ENDIF
IF unit_price < 20
SKIP
LOOP
ENDIF
gnStockTot = gnStockTot + in_stock
SKIP
ENDDO && Ends loop
CLEAR
? 'Total items in stock valued over 20 dollars:'
?? gnStockTot | |