How To Step Through C Code Dev
How to use Dev-C Introduction Dev-C is a full-featured integrated development environment (IDE), which is able to create Windows or DOS-based C/C programs using the Mingw compiler system (included with the package), or the Cygwin compiler. Oct 28, 2019 Brief: This tutorial teaches you to run C and C programs in Linux terminal.It also show the steps to setup a C development environment in Ubuntu Linux using Eclipse IDE. I have been requested more than once about writing an easy to follow tutorial to run C program in Linux. In this guide, I’ll show you. Dec 05, 2013 If you want to really understand what’s going on in your program at a given point in time you need to be using a step-through debugger. Step-through debuggers are commonplace among compiled languages but for whatever reason in web development, at least in my experience, they haven’t seemed to catch on. After that, do a full rebuild (Ctrl-F11), then set breakpoint(s) where you want the debugger to stop (otherwise it will just run the program). To set a breakpoint on a line, just click on the gutter (the gray band on the left), or press Ctrl-F5. Now you are ready to launch the debugger, by pressing F8 or clicking the debug button.
What is Dev-C++?
Dev-C++, developed by Bloodshed Software, is a fully featured graphical IDE (Integrated Development Environment), which is able to create Windows or console-based C/C++ programs using the MinGW compiler system. MinGW (Minimalist GNU* for Windows) uses GCC (the GNU g++ compiler collection), which is essentially the same compiler system that is in Cygwin (the unix environment program for Windows) and most versions of Linux. There are, however, differences between Cygwin and MinGW; link to Differences between Cygwin and MinGW for more information.
Bloodshed!?
I'll be the first to say that the name Bloodshed won't give you warm and fuzzies, but I think it's best if the creator of Bloodshed explains:
There's also a reason why I keep the Bloodshed name. I don't want people to think Bloodshed is a company, because it isn't. I'm just doing this to help people.
Here is a good remark on the Bloodshed name I received from JohnS:
I assumed that this was a reference to the time and effort it requires of you to make these nice software programs, a la 'Blood, Sweat and Tears'.
Peace and freedom,
Colin Laplace
Getting Dev-C++
The author has released Dev-C++ as free software (under GPL) but also offers a CD for purchase which can contain all Bloodshed software (it's customizable), including Dev-C++ with all updates/patches.
Link to Bloodshed Dev-C++ for a list of Dev-C++ download sites.
You should let the installer put Dev-C++ in the default directory of C:Dev-Cpp, as it will make it easier to later install add-ons or upgrades.
Using Dev-C++
This section is probably why you are here.
All programming done for CSCI-2025 will require separate compilation projects (i.e. class header file(s), class implementation file(s) and a main/application/client/driver file). This process is relatively easy as long as you know what Dev-C++ requires to do this. In this page you will be given instructions using the Project menu choice. In another handout you will be given instructions on how to manually compile, link and execute C++ files at the command prompt of a command window. See here.
Step 1: Configure Dev-C++.
We need to modify one of the default settings to allow you to use the debugger with your programs.
- Go to the 'Tools' menu and select 'Compiler Options'.
- In the 'Settings' tab, click on 'Linker' in the left panel, and change 'Generate debugging information' to 'Yes':
- Click 'OK'.
Step 2: Create a new project.
A 'project' can be considered as a container that is used to store all the elements that are required to compile a program.
- Go to the 'File' menu and select 'New', 'Project..'.
- Choose 'Empty Project' and make sure 'C++ project' is selected.
Here you will also give your project a name. You can give your project any valid filename, but keep in mind that the name of your project will also be the name of your final executable. - Once you have entered a name for your project, click 'OK'.
- Dev-C++ will now ask you where to save your project.
Step 3: Create/add source file(s).
You can add empty source files one of two ways:
- Go to the 'File' menu and select 'New Source File' (or just press CTRL+N) OR
- Go to the 'Project' menu and select 'New File'.
Note that Dev-C++ will not ask for a filename for any new source file until you attempt to:- Compile
- Save the project
- Save the source file
- Exit Dev-C++
- Go to the 'Project' menu and select 'Add to Project' OR
- Right-click on the project name in the left-hand panel and select 'Add to Project'.
EXAMPLE: Multiple source files In this example, more than 3 files are required to compile the program; The 'driver.cpp' file references 'Deque.h' (which requires 'Deque.cpp') and 'Deque.cpp' references 'Queue.h' (which requires 'Queue.cpp'). |
Step 4: Compile.
Once you have entered all of your source code, you are ready to compile.
- Go to the 'Execute' menu and select 'Compile' (or just press CTRL+F9).
It is likely that you will get some kind of compiler or linker error the first time you attempt to compile a project. Syntax errors will be displayed in the 'Compiler' tab at the bottom of the screen. You can double-click on any error to take you to the place in the source code where it occurred. The 'Linker' tab will flash if there are any linker errors. Linker errors are generally the result of syntax errors not allowing one of the files to compile.
Step 5: Execute.
You can now run your program.
- Go to the 'Execute' menu, choose 'Run'.
Disappearing windows
If you execute your program (with or without parameters), you may notice something peculiar; a console window will pop up, flash some text and disappear. The problem is that, if directly executed, console program windows close after the program exits. You can solve this problem one of two ways:
- Method 1 - Adding one library call:
On the line before the main's return enter:system('Pause');
- Method 2 - Scaffolding:
Add the following code before any return statement in main() or any exit() or abort() statement (in any function):/* Scaffolding code for testing purposes */
This will give you a chance to view any output before the program terminates and the window closes.
cin.ignore(256, 'n');
cout << 'Press ENTER to continue..'<< endl;
cin.get();
/* End Scaffolding */ - Method 3 - Command-prompt:
Alternatively, instead of using Dev-C++ to invoke your program, you can just open an MS-DOS Prompt, go to the directory where your program was compiled (i.e. where you saved the project) and enter the program name (along with any parameters). The command-prompt window will not close when the program terminates.
For what it's worth, I use the command-line method.
Step 6: Debug.
When things aren't happening the way you planned, a source-level debugger can be a great tool in determining what really is going on. Dev-C++'s basic debugger functions are controlled via the 'Debug' tab at the bottom of the screen; more advanced functions are available in the 'Debug' menu.
Using the debugger:
The various features of the debugger are pretty obvious. Click the 'Run to cursor' icon to run your program and pause at the current source code cursor location; Click 'Next Step' to step through the code; Click 'Add Watch' to monitor variables.
Setting breakpoints is as easy as clicking in the black space next to the line in the source code.
See the Dev-C++ help topic 'Debugging Your Program' for more information.
Dev-C++ User F.A.Q.
Why do I keep getting errors about 'cout', 'cin', and 'endl' being undeclared?
It has to do with namespaces. You need to add the following line after the includes of your implementation (.cpp) files:
How do I use the C++ string class?
Again, it probably has to do with namespaces. First of all, make sure you '#include <string>' (not string.h). Next, make sure you add 'using namespace std;' after your includes.
Example:
That's it for now.I am not a Dev-C++ expert by any means (in fact, I do not teach C++ nor use it on a regular basis), but if you have any questions, feel free to email me at jaime@cs.uno.edu
Happy coding!
In this tutorial, you will configure Visual Studio Code to use the GCC C++ compiler (g++) and GDB debugger on Ubuntu in the Windows Subsystem for Linux (WSL). GCC stands for GNU Compiler Collection; GDB is the GNU debugger. WSL is a Linux environment within Windows that runs directly on the machine hardware, not in a virtual machine.
Note: Much of this tutorial is applicable to working with C++ and VS Code directly on a Linux machine.
Visual Studio Code has support for working directly in WSL with the Remote - WSL extension. We recommend this mode of WSL development, where all your source code files, in addition to the compiler, are hosted on the Linux distro. For more background, see VS Code Remote Development.
After completing this tutorial, you will be ready to create and configure your own C++ project, and to explore the VS Code documentation for further information about its many features. This tutorial does not teach you about GCC or Linux or the C++ language. For those subjects, there are many good resources available on the Web.
If you have any problems, feel free to file an issue for this tutorial in the VS Code documentation repository.
Prerequisites
To successfully complete this tutorial, you must do the following steps:
Install Visual Studio Code.
Install the Remote - WSL extension.
Install Windows Subsystem for Linux and then use the links on that same page to install your Linux distribution of choice. This tutorial uses Ubuntu. During installation, remember your Linux user password because you'll need it to install additional software.
Set up your Linux environment
Open the Bash shell for WSL. If you installed an Ubuntu distro, type 'Ubuntu' in the Windows search box and then click on it in the result list. For Debian, type 'Debian', and so on.
The shell appears with a command prompt that by default consists of your user name and computer name, and puts you in your home directory. For Ubuntu it looks like this:
Make a directory called
projects
and then subdirectory under that calledhelloworld
:Although you will be using VS Code to edit your source code, you'll be compiling the source code on Linux using the g++ compiler. You'll also debug on Linux using GDB. These tools are not installed by default on Ubuntu, so you have to install them. Fortunately, that task is quite easy!
From the WSL command prompt, first run
apt-get update
to update the Ubuntu package lists. An out-of-date distro can sometimes interfere with attempts to install new packages.If you like, you can run
sudo apt-get update && sudo apt-get dist-upgrade
to also download the latest versions of the system packages, but this can take significantly longer depending on your connection speed.From the command prompt, install the GNU compiler tools and the GDB debugger by typing:
Verify that the install succeeded by locating g++ and gdb. If the filenames are not returned from the
whereis
command, try running the update command again.
Note: The setup steps for installing the g++ compiler and GDB debugger apply if you are working directly on a Linux machine rather than in WSL. Running VS Code in your helloworld project, as well as the editing, building, and debugging steps are the same.
Run VS Code in WSL
Navigate to your helloworld project folder and launch VS Code from the WSL terminal with code .
:
You'll see a message about 'Installing VS Code Server'. VS Code is downloading and installing a small server on the Linux side that the desktop VS Code will then talk to. VS Code will then start and open the helloWorld
folder. The File Explorer shows that VS Code is now running in the context of WSL with the title bar [WSL: Ubuntu].
You can also tell the remote context from the Status bar.
If you click on the Remote Status bar item, you will see a dropdown of Remote commands appropriate for the session. For example, if you want to end your session running in WSL, you can select the Close Remote Connection command from the dropdown. Running code .
from your WSL command prompt will restart VS Code running in WSL.
The code . command opened VS Code in the current working folder, which becomes your 'workspace'. As you go through the tutorial, you will see three files created in a .vscode
folder in the workspace:
c_cpp_properties.json
(compiler path and IntelliSense settings)tasks.json
(build instructions)launch.json
(debugger settings)
Add a source code file
In the File Explorer title bar, select the New File button and name the file helloworld.cpp
.
Install the C/C++ extension
Once you create the file and VS Code detects it is a C++ language file, you may be prompted to install the Microsoft C/C++ extension if you don't already have it installed.
Choose Install and then Reload Required when the button is displayed in the Extensions view to complete installing the C/C++ extension.
If you already have C/C++ language extensions installed locally in VS Code, you'll need to go to the Extensions view (⇧⌘X (Windows, Linux Ctrl+Shift+X)) and install those extensions into WSL. Locally installed extensions can be installed into WSL by selecting the Install in WSL button and then Reload Required.
Add hello world source code
Now paste in this source code:
Now press ⌘S (Windows, Linux Ctrl+S) to save the file. Notice how the file you just added appears in the File Explorer view (⇧⌘E (Windows, Linux Ctrl+Shift+E)) in the side bar of VS Code:
You can also enable Auto Save to automatically save your file changes, by checking Auto Save in the main File menu.
The Activity Bar on the far left lets you open different views such as Search, Source Control, and Run. You'll look at the Run view later in this tutorial. You can find out more about the other views in the VS Code User Interface documentation.
Explore IntelliSense
In your new helloworld.cpp
file, hover over vector
or string
to see type information. After the declaration of the msg
variable, start typing msg.
as you would when calling a member function. You should immediately see a completion list that shows all the member functions, and a window that shows the type information for the msg
object:
You can press the Tab key to insert the selected member; then, when you add the opening parenthesis, you will see information about any arguments that the function requires.
Build helloworld.cpp
Next, you will create a tasks.json
file to tell VS Code how to build (compile) the program. This task will invoke the g++ compiler on WSL to create an executable file based on the source code.
From the main menu, choose Terminal > Configure Default Build Task. In the dropdown, which will display a tasks dropdown listing various predefined build tasks for C++ compilers. Choose g++ build active file, which will build the file that is currently displayed (active) in the editor.
This will create a tasks.json
file in a .vscode
folder and open it in the editor.
Your new tasks.json
file should look similar to the JSON below:
The command
setting specifies the program to run; in this case that is g++. The args
array specifies the command-line arguments that will be passed to g++. These arguments must be specified in the order expected by the compiler. This task tells g++ to take the active file (${file}
), compile it, and create an executable file in the current directory (${fileDirname}
) with the same name as the active file but without an extension (${fileBasenameNoExtension}
), resulting in helloworld
for our example.
Note: You can learn more about task.json
variables in the variables reference.
The label
value is what you will see in the tasks list; you can name this whatever you like.
The 'isDefault': true
value in the group
object specifies that this task will be run when you press ⇧⌘B (Windows, Linux Ctrl+Shift+B). This property is for convenience only; if you set it to false, you can still run it from the Terminal menu with Tasks: Run Build Task.
Running the build
Go back to
helloworld.cpp
. Your task builds the active file and you want to buildhelloworld.cpp
.To run the build task defined in
tasks.json
, press ⇧⌘B (Windows, Linux Ctrl+Shift+B) or from the Terminal main menu choose Tasks: Run Build Task.When the task starts, you should see the Integrated Terminal panel appear below the source code editor. After the task completes, the terminal shows output from the compiler that indicates whether the build succeeded or failed. For a successful g++ build, the output looks something like this:
Create a new terminal using the + button and you'll have a bash terminal running in the context of WSL with the
helloworld
folder as the working directory. Runls
and you should now see the executablehelloworld
(no file extension).You can run
helloworld
in the terminal by typing./helloworld
.
Modifying tasks.json
You can modify your tasks.json
to build multiple C++ files by using an argument like '${workspaceFolder}/*.cpp'
instead of ${file}
. You can also modify the output filename by replacing '${fileDirname}/${fileBasenameNoExtension}'
with a hard-coded filename (for example 'helloworld.out').
Debug helloworld.cpp
Next, you'll create a launch.json
file to configure VS Code to launch the GDB debugger when you press F5 to debug the program. From the main menu, choose Run > Add Configuration.. and then choose C++ (GDB/LLDB).
You'll then see a dropdown for various predefined debugging configurations. Choose g++ build and debug active file.
VS Code creates a launch.json
file, opens it in the editor, and builds and runs 'helloworld'.
The program
setting specifies the program you want to debug. Here it is set to the active file folder ${fileDirname}
and active filename without an extension ${fileBasenameNoExtension}
, which if helloworld.cpp
is the active file will be helloworld
.
By default, the C++ extension won't add any breakpoints to your source code and the stopAtEntry
value is set to false
. Change the stopAtEntry
value to true
to cause the debugger to stop on the main
method when you start debugging.
The remaining steps are provided as an optional exercise to help you get familiar with the editing and debugging experience.
Start a debugging session
- Go back to
helloworld.cpp
so that it is the active file. - Press F5 or from the main menu choose Run > Start Debugging. Before you start stepping through the code, let's take a moment to notice several changes in the user interface:
The Integrated Terminal appears at the bottom of the source code editor. In the Debug Output tab, you see output that indicates the debugger is up and running.
The editor highlights the first statement in the
main
method. This is a breakpoint that the C++ extension automatically sets for you:The Run view on the left shows debugging information. You'll see an example later in the tutorial.
At the top of the code editor, a debugging control panel appears. You can move this around the screen by grabbing the dots on the left side.
Step through the code
Now you're ready to start stepping through the code.
Click or press the Step over icon in the debugging control panel.
This will advance program execution to the first line of the for loop, and skip over all the internal function calls within the
vector
andstring
classes that are invoked when themsg
variable is created and initialized. Notice the change in the Variables window on the left.In this case, the errors are expected because, although the variable names for the loop are now visible to the debugger, the statement has not executed yet, so there is nothing to read at this point. The contents of
msg
are visible, however, because that statement has completed.Press Step over again to advance to the next statement in this program (skipping over all the internal code that is executed to initialize the loop). Now, the Variables window shows information about the loop variables.
Press Step over again to execute the
cout
statement. (Note that as of the March 2019 release, the C++ extension does not print any output to the Debug Console until the loop exits.)If you like, you can keep pressing Step over until all the words in the vector have been printed to the console. But if you are curious, try pressing the Step Into button to step through source code in the C++ standard library!
To return to your own code, one way is to keep pressing Step over. Another way is to set a breakpoint in your code by switching to the
helloworld.cpp
tab in the code editor, putting the insertion point somewhere on thecout
statement inside the loop, and pressing F9. A red dot appears in the gutter on the left to indicate that a breakpoint has been set on this line.Then press F5 to start execution from the current line in the standard library header. Execution will break on
cout
. If you like, you can press F9 again to toggle off the breakpoint.When the loop has completed, you can see the output in the Debug Console tab of the integrated terminal, along with some other diagnostic information that is output by GDB.
Set a watch
Sometimes you might want to keep track of the value of a variable as your program executes. You can do this by setting a watch on the variable.
Place the insertion point inside the loop. In the Watch window, click the plus sign and in the text box, type
word
, which is the name of the loop variable. Now view the Watch window as you step through the loop.Add another watch by adding this statement before the loop:
int i = 0;
. Then, inside the loop, add this statement:++i;
. Now add a watch fori
as you did in the previous step.To quickly view the value of any variable while execution is paused on a breakpoint, you can hover over it with the mouse pointer.
C/C++ configurations
If you want more control over the C/C++ extension, you can create a c_cpp_properties.json
file, which will allow you to change settings such as the path to the compiler, include paths, C++ standard (default is C++17), and more.
You can view the C/C++ configuration UI by running the command C/C++: Edit Configurations (UI) from the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)).
This opens the C/C++ Configurations page. When you make changes here, VS Code writes them to a file called c_cpp_properties.json
in the .vscode
folder.
You only need to modify the Include path setting if your program includes header files that are not in your workspace or in the standard library path.
Visual Studio Code places these settings in .vscode/c_cpp_properties.json
. If you open that file directly, it should look something like this:
Closing the WSL session
When you are done working in WSL, you can close your remote session with the Close Remote Connection command available in the main File menu and the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)). This will restart VS Code running locally. You can easily reopen your WSL session from the File > Open Recent list by selecting folders with the [WSL] suffix.
How To Step Through C Code Dev 2017
Next steps
How To Step Through C Code Dev 2
- Explore the VS Code User Guide.
- Review the Overview of the C++ extension.
- Create a new workspace, copy your .json files to it, adjust the necessary settings for the new workspace path, program name, and so on, and start coding!