Flow-control structures: Difference between revisions
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===Interruptions to the flow===
More potent than RETURN is STOP, which ends the flow of execution there and then - without the need to signal some sort of "disaster" status so that each level of a nest of routines would return to its caller. Early Fortran also allowed STOP ''n'' where ''n'' was a number such as 303 and this value might be displayed on the computer's console display register in bright lights, or be printed in the job log, or on the standard output device. A later extension was STOP "message", but alas the message is only a fixed text, one can't devise a custom report such as "307 values!
Instead of STOP, there is PAUSE with the same syntax. The flow of execution would pause (that is, the entire computer would come to a stop in the days when one job only would run at a time), to be resumed with the next statement on the pressing of a button on the computer console for instance after the message "Attach output tape", or, ... the operator could via controls on the console inspect memory (on the decimal IBM1620, even floating-point numbers were easily parsed), modify memory, and cause execution to resume at some other (any other) chosen address...
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