1 / 18

ME 142 Engineering Computation I

ME 142 Engineering Computation I. Debugging Techniques. Key Concepts. Types of Program Errors Debugging Tools & Techniques Testing. Types of Programming Errors. Syntax Errors Run-Time Errors Logic Errors. Syntax Errors.

josephine-kirkland
Télécharger la présentation

ME 142 Engineering Computation I

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ME 142Engineering Computation I Debugging Techniques

  2. Key Concepts • Types of Program Errors • Debugging Tools & Techniques • Testing

  3. Types of Programming Errors • Syntax Errors • Run-Time Errors • Logic Errors

  4. Syntax Errors • Syntax errors occur when the rules of the programming language are violated. • Examples: • Misspelling a keyword or function name • Misplacement or omission of a parenthesis or quote mark • Omission of necessary keywords in a command.

  5. Run-Time Errors • Runtime errors are those errors that occur when a program free of syntax errors, runs and generates an error. • Examples: • Attempting an invalid operation such as division by zero • Providing the wrong data type to a function.

  6. Logic Errors • Logic errors are due to incorrect program logic. • The program may run without errors • The results it returns are inaccurate. • Often the most difficult to locate

  7. Debugging Tools & Techniques • MsgBox Function • Debug.Print Statement • Debug Mode

  8. MsgBox Statement • Place MsgBox statement in your code as desired • Causes the value of the variables to be immediately displayed in a dialog box and pauses execution of program • Example: MsgBox (“A = “ & A)

  9. Debug.Print Statement • Place Debug.Print statement in your code as you would MsgBox function • Causes the value of the variables to be printed in the Immediate window • Example: Debug.Print A,B,C

  10. Debug.Print Statement

  11. Debug Mode • Allows you step through your program and examine the value of variables at specific points • May step through line-by-line or set specific breakpoints

  12. Debug Mode • When a run-time error occurs may enter Debug Mode by selecting button on dialog box that appears:

  13. Debug Mode • Once in Debug Mode may mouse-over a variable to find its current value:

  14. Debug Mode • May also hit the F8 key to single step through the program • Each time the F8 key is hit, one line of code is executed:

  15. Debug Mode • May also set a breakpoint by clicking in the gray column on the left side of the line of code you want to program to pause on • Click on run (from menu above) to cause the program to resume

  16. Debug Mode • Another powerful feature to use in conjunction with the previous techniques is the Locals Window • It displays the current value of all local variables in your program

  17. Testing • Deadly Misconception of Beginning Programmers: • If a program runs without errors, the results must be correct • Very important that before you use your program to make engineering decisions (or turn it in to get a grade in class) that you perform a series of test to make certain that the output is correct.

  18. Testing Suggestions • Compare your results to that of a simple, known problem by using a calculator or Excel • Test a typical range of inputs • Test unusual but valid data • Test extreme values

More Related