Debugging Tactics

Question 1

Basic debugging tactics

Answer 1

• commenting out the code
• validating the code flow
• printing values

Question 2

Validating code flow

Answer 2

Used when the program is calling to a function too many or few times.

Question 3

Using validating code flow

Answer 3

By placing statements at the top of the function to print the functions name
Use std::cerr and do not indent the debug statements

Question 4

Printing values

Answer 4

Used when the program is calculating or passing wrong value

Question 5

Using printing values

Answer 5

By outputting the value of variables and expressions by using std::cerr

Question 6

Why not to use debug statements

Answer 6

• clutter the code
• clutter the output of the program
• must be removed, it is not reusable
• requires modification which can introduce new bugs

Question 7

Conditionalizing the debugging code

Answer 7

To make the debugging statements conditional using preprocessor directives

Question 8

Using conditionalizing the debugging code

Answer 8

With #define ENABLE_DEBUG by commenting/uncommenting it

Question 9

Conditionalizing the debugging code in multi-file program

Answer 9

Use #define ENABLE_DEBUG in a header file in all code files

Question 10

Log file

Answer 10

File stored in disk, that records events that occur in the software

Question 11

Logging

Answer 11

Process of writing information to a log file

Question 12

Advantages of log file

Answer 12

• aviding clutter, because it is stored on a separate file

* can be sent to others for diagnosis

Question 13

Program state

Answer 13

Tracked value of variables , called function and current point of execution within the program

Question 14

Debugger

Answer 14

Computer program that allows the programer to control how a program executes and examin the program state while the program is running

Question 15

Advantige of debugger

Answer 15

Ability to precisily control execution of the program and ability to view/modify program’s state

Question 16

Stepping

Answer 16

Set of related debugger features that let us execute (step through) our code statement by statement

Question 17

Step into

Answer 17

That executes the next statement in the normal execution path of the program, and pauses so you can inspect the code

Question 18

Stepping into without running

Answer 18

• the program will recompile
• will begin to run
• will open diagnostic windows

Question 19

Step over

Answer 19

Executes an entire function without stepping, use it when you know a function works

Question 20

Step out

Answer 20

Executes remaining code in the function currently being executed, use it when you accidentally stepped into a function that you don’t want to debug

Question 21

Step back

Answer 21

Rewind the last step, so you can return the program to a prior state

Question 22

Run to cursor

Answer 22

Executes the prigram until the execution reaches the statement selected by your cursor, then it returns the control to you

Question 23

Continue

Answer 23

Continues runnung the program as per normal, either until the program terminates or until something triggers control to return back

Question 24

Start

Answer 24

Running the program fromthe begining, it can be invoked when not already in a debug session

Question 25

Breakpoint

Answer 25

Tells the debugger to stop executing the program at the breakpoint when running in debug mode

Question 26

Advantages of breakpoints

Answer 26

* return control everytime they are encountered | * you can set a breakpoint and it will persist until you remove it

Question 27

Set next statement

Answer 27

Changes the point of execution to some other statement (jumping), you can jump forwards and backwards

Question 28

Watching variables

Answer 28

Process of inspecting the value of a variable while the program is executing in debug mode.

Question 29

Ways to watch variables

Answer 29

* hovering the mouse over variables | * quickWatch in the right-click menu

Question 30

Watch window

Answer 30

Window where you can add variables you like to continually inspect, will be updated as you step trough

Question 31

Ways to add variables to watch window

Answer 31

* trough watch window by typing the name of the variable in the left column * trough code window by right-click on variable and add watch

Question 32

Watching out of scope variables

Answer 32

Will stay on the window, but will be marked as not available or show the last kmown value but it will be grayed out

Question 33

Other watch window use

Answer 33

Evaluating simple expressions

Question 34

Local watches

Answer 34

Quick way to watch value of local variables in scope

Question 35

Call stack

Answer 35

List of all the active functions that have been called to get to the current point of execution

Question 36

Included in the call stack

Answer 36

Entry for each function called and which line of code will be returned to when the function returns

Question 37

Adding functions to the call stack

Answer 37

The function is added to the top of the stack, when it's returned the function is removed from the top of the stack and the control is returned to the function below it

Question 38

Call stack window

Answer 38

Debugger window that shows the current call stack

Question 39

Use for call stacks

Answer 39

In conjunction with breakpoints, when your breakpoint is hit and you want to know what functions were called to get to that point of code

Question 40

Things that can help avoid making errors

Answer 40

* follow the best practices * don't program when tired * understand where the common pitfalls are in a language * keep your programs simple * don't let your functions to get too long * preder using the standard library to writing your own code * comment liberary

Question 41

Refacturing

Answer 41

Process of making strucrltural changes to your code without changing it's behaviour

Question 42

Making behavioural and structural changes

Answer 42

At the same time tends to lead to more errors

Question 43

Defensive programming

Answer 43

Practice where the programmer tries to anticipate all the ways the software could be mis-used by end-users or developers using the code

Question 44

Programming a little bit a time

Answer 44

Fast way to find errors especialy if you test the code and make sure it works

Question 45

Testing functions

Answer 45

Primitive form of unit testing, by which a small unit of source code are tested to determine whether they are correct

Question 46

Use of testing functions

Answer 46

Ex. testadd(), tests the function by calling it with different values

Question 47

Constrains

Answer 47

Involve the addition of some extra code to check that some set of assumptions or expectations are not violated

Question 48

Static analysis tools (linters)

Answer 48

Programs that analyze your code to identify specific semantic issues