Flow control

Process flow control functions are the functions that execute the decision making and resultant logic branches in executable code. IF-THEN-ELSE, discussed in Chapter 6, Introduction to C/SIDE and C/AL, is also a member of this class of functions. Here, we will discuss the following:

• REPEAT - UNTIL
• WHILE - DO
• FOR-TO and FOR-DOWNTO
• CASE - ELSE
• WITH - DO
• QUIT, BREAK, EXIT, and SKIP

 

REPEAT-UNTIL

REPEAT-UNTIL allows us to create a repetitive code loop, which REPEATs a block of code UNTIL a specific conditional expression evaluates to TRUE. In that sense, REPEAT-UNTIL defines a block of code, operating somewhat like the BEGIN-END compound statement structure that we covered in Chapter 6, Introduction to C/SIDE and C/AL. REPEAT tells the system to keep reprocessing the block of code, while the UNTIL serves as the exit doorman, checking if the conditions for ending the processing are true. Because the exit condition is not evaluated until the end of the loop, a REPEAT-UNTIL structure will...