Debug

First, the concept of program debugging

Program debugging is the process of testing
, correcting syntax errors and logic errors by hand or compiling the program before putting it into actual operation.

Second, program debugging steps

1. Find the existence of program errors.
2. Locate the found error
3. Find out the cause of the error
4. Correct the error
5. Re-test the corrected program

Third, debugging in Windows environment

We use VS to debug in the Windows environment, and gdb in the linux environment.Debugging on VS is divided into two versions: Debug version and release version.
Debug version contains program debugging information without optimization.
The release version has carried out various optimizations to the program, so that the size and speed of the program code have been improved.Mainly for user use.
You can compare the running size of the two versions, as shown in the figure:

Obviously debug is much bigger than release.Normal debugging can only be performed under the debug version.

Fourth, debugging shortcuts

F5: Start debugging, often used to jump directly to the next breakpoint.
F9: The important role of creating breakpoints and canceling breakpoints. Breakpoints can be set anywhere in the program.In this way, the program can be stopped at the desired position at will, and then executed step by step.
F10: by procedure, used to process a procedure can be a function call, or a statement.
F11: statement by statement, execute a statement each time, this shortcut key can make our execution logic enter the function.

5. What debugging can do

1. View the value of the temporary variable

Enter debugging, initialize the a array to 0 in the code as shown in the figure, and enter a in the monitor, and the values ​​from 0 to 9 will be initialized to 0 as shown in the figure:

2. View memory information

Enter a in the memory to display the addresses of these 10 numbers:

Of course, you can also see &a in the monitor, for example, enter &a[1], &a[9].As shown:

3. View the call stack

From the picture, we can see that the program only calls one main function.

4. View assembly information

5. View register information

6. Common compilation errors

(1), compilation error

Look directly at the error message in the box below, or solve it with your own experience

(2), link error

Look at the error message and find the identifier in the error message in the code. Generally, the identifier name does not exist or is misspelled. For example, main is written as mian or a non-existent function name is written.

(3), runtime error

This is relatively hard to find and requires debugging to gradually locate the error.