Turbo Basic

THON and THOFF commandsFunctionSyntaxRemarksDifferencesTRON and TROFF tum on and off execution trace.TRON (trace on)TROFF (trace off)TRONputs your program into a debugging mode in which. sourceline numbers, statement labels, and procedure and function namesare sent to the Trace window as each statement is executed; TROFFturns this debugging mode off.When running in text mode under Turbo Basic, the trace linenumbers, labels, and procedure and function names are sent to theTrace window.While tracing, press Alt-F9 to alternate between tracing and executing.Use Alt-F 10 to single-step to the next line number, label, orprocedure or function name.Unlike Interpretive BASIC, in Turbo Basic the physical position ofTRON and TROFF in your source program controls their effectrather than their position in the run-time execution path. For example,consider this program:10 GOTO 3020 TRON30 x = y + z40 TROFF50 ENDWhen executing this program,. Interpretive BASIC will nevertum on the trace, because as far as it's concerned the TRON statementin line 20 doesn't exist. Turbo,Basic, on the other hand, makestrace/no trace decisions at compile time and considers all statementsafter the appearance ofTRON as being turned on for tracing. There-:­fore, a Turbo Basic-produced program will output:[30] [40]when the preceding program runs.Turbo Basic Reference Directory 363