programming-for-dummies

Fixing a Program with a Debugger 99
A breakpoint lets you tell the computer, “Skip from the beginning of the program
to the breakpoint and then step through the rest of the program line by
line.” Figure 4-6 shows how you can highlight a line with a breakpoint. That
way your program runs from the beginning to the first breakpoint. After your
program stops at a breakpoint, you can step through the rest of your program
line by line.
Book I
Chapter 4
Programming Tools
Figure 4-6:
Breakpoints
let you skip
over parts of
your
program
that you
don’t want
to examine
line by line.
Over and out
The stepping over and stepping out commands are used to debug a large
program that consists of multiple subprograms. Normally, stepping would
force you to examine every subprogram, line by line. However, what if you
know the problem isn’t in a specific subprogram?
By using the step over and step out commands, you can avoid stepping
through lines of code stored in a subprogram.
Step over
To avoid stepping through every subprogram, debuggers let you use the
step over command. This tells the computer, “See that entire subprogram?
Treat it as a single command and don’t bother stepping through it line by
line.” Figure 4-7 shows how the step over command works.
The step over command lets you completely skip over any lines of code
stored inside of a subprogram.