Progress
Language Reference
IF...THEN...ELSE Statement
Makes the execution of a statement or block of statements conditional. If the value of the expression following the IF statement is TRUE, Progress processes the statements following the THEN statement. Otherwise, Progress processes the statements following the ELSE statement.
SYNTAX
expression
A constant, field name, variable name, or expression whose value is logical (TRUE or FALSE). The expression can include comparisons, logical operators, and parentheses.
THEN
Describes the block statement to process if the expression is TRUE.
block
The block statement that contains the code you want to process if expression is TRUE. See the DO Statement, FOR Statement, and REPEAT Statement reference entries for more information. If you do not start a block, you can process just one statement after the IF keyword or the ELSE keyword.
Any block or blocks you use in an IF . . . THEN . . . ELSE statement can contain other blocks or other IF . . . THEN . . . ELSE statements.
statement
A single Progress statement. The statement can be another IF . . . THEN . . . ELSE statement. If you want to use more than one statement, enclose those statements in a DO, FOR EACH, or REPEAT block.
ELSE
Describes the block statement to process if the expression is FALSE or unknown (?). The ELSE option is not required.
EXAMPLEThe
r-ifelss.p
procedure creates a report in a file that lists customers whose orders have been shipped but who have not paid for those orders.
First, the procedure writes report headers to the
ovrdue.lst
file. Next, the outer FOR EACH block reads each of the orders using a DISPLAY statement to display information on each order. If there are no values in the ship-date and promise-date fields, the procedure prompts you to enter a promise date. The procedure then prompts if the order has been shipped. If it has, supply a ship date.If there is a ship date and a promise date for an order, the procedure prompts if the order has been paid for. If not, the procedure displays the order information to the file.
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