Beginning Programming with C++ For Dummies®

Chapter 20. Debugging Your Programs, Part 3

In This Chapter

• Debugging using the built-in debugger

• Building your application with debugger information

• Setting a breakpoint

• Single-stepping your program

• Fixing a sample problem

I introduced a few techniques for finding errors at the end of Parts II (Chapter 8) and III (Chapter 13). Now that you are nearing the end of Part IV, I want to touch on debugging techniques one final time.

In this chapter, I introduce you to the debugging tools built into the Code::Blocks development environment (similar tools exist for most other environments). Learning to use the debugger will give you clear insight into what your program is doing (and what it's not doing, at times).

A New Approach to Debugging

Chapters 8 and 13 demonstrated how to find problems by adding output statements in key positions. Outputting key variables lets you see what intermediate values your program is calculating and what path it's taking through your C++ code.

However, the output technique has several distinct disadvantages. The first is that it's difficult to know what to display. In a small program, such as most of the programs in this book, you can display almost everything — there just aren't that many variables to slug through. However, in a major league program, there may be many hundreds of variables, especially if you include all of the elements in the arrays. Knowing which variables to display can be problematic.

A second problem is the time it takes to rebuild the program. ...