VB – Debugging Tools

1. VB – Debugging Tools Appendix D

2. Why do we need debugging? • Every program has errors, and the process of finding these errors is debugging • Types of errors • Syntax Errors • Run Time Errors • Logic Errors

3. Debugging and Modes • VB has three modes • Design • Run • Break • Syntax Errors show up during design mode • Run Time Errors show up during run mode and invoke break mode • When do Logic errors show up?

4. Syntax Errors • How do they show up?????

5. Run Time Errors • How about them???

6. Logic Errors • Well??? • I’m waiting • Maybe a good start is to find out what they really are

7. Visual Basic 6.0 Tools • Immediate Window – You can type a statement in the immediate window, press enter, and the stmt you typed is executed. • The Immediate window is used to find what the value of variables are when the programmer selects the break mode

8. Visual Basic 6.0 Tools p-2 • Watch Window – is used to monitor (watch) an expression or a break expression. • At any time, the watch window shows the current values of all watch and break expressions • We add expressions to the Watch Window by right-click on a variable in the code window and add to watch. We can also edit and delete expressions.

9. Visual Basic 6.0 Tools p-3 • Locals Window – displays the names, values, and types of all variables in the current procedure. • Values of variables can be altered at any time in this window • Properties of objects can be modified through this window as well

10. STEP • Step Through – F8 – line by line • Step Over – Shift / F8 – skip a procedure • Step Out – Ctrl / Shift / F8 – execute remainder • These are handled manually with these key strokes, I use them all the time

11. BreakPoints • Setting – F9 Program will execute up to this point • Removing – F9 • Clear All - Ctrl / Shift / F9 • Set next Stmt – Ctrl / F9 • Continue or Advance – F5 • Run to cursor – Ctrl / F8