Several researchers have tried to find an Adacsk programis repeating several steps: executing effective way to represent execution is easier with this test programs, detecting errors, behavior for program debugging. Cargill's visual debugger that investigating their causes, correcting them, Blit debugger' uses multiple windows that graphically depicts and recompiling. The most timesimultaneously show program execution consuming, difficult step is the detection output, interaction with the debugger, and what the program as and investigation of errors. program text. Myers' Incense debugger' doingand how Traditional debugging tools return displays the variables' data structures, but it is being done. character-based information, such as does not address the dynamic features of traces or dumps of statement numbers and program execution. Reiss' Pecan variable values. This method forces the debugger3does propose dynamic presenprogrammer to perceive and locate errors tation of the control flow on a program based on clues hidden in the information, flowchart, but it displays character-based A debugging tool should show the pro-data just like traditional debugging tools. gram's static and dynamic behavior so the The Balsa' and program visualization' programmer can easily understand what systems can represent data in figures that the program is doing and how it is being are appropriate to their meaning. However, executed. they do not have facilities to represent con-8 0740-7459/87/0300/0008/$01.O0 ©1A987 IEEE IEEE SOFTWARE