Multiple main C++ files in a single project in Code::Blocks? - c++

I do not regularly write code. There are times I write code daily for 6 months, and then do not code for up to 2 years. This approach has forced me to keep a bunch or reference code that I (and other much, much better programmers) have written. I refer to this "library" when writing code after a long period; I read it, I execute it, and that is a massive help in refreshing myself. This system has served me very well with Eclipse & Java over the past 5 years.
I am now learning C++ and am using Code::Blocks. I would like to somehow stuff a bunch of C++ files that have main methods into a single Code::Blocks project. I am willing to rewrite the code to achieve this task (if it's reasonable...)
I am not the first to look for a meaningful answer for this issue: https://stackoverflow.com/questions/35917504/how-can-i-make-multiple-programs-in-a-single-project-in-codeblocks and https://www.reddit.com/r/learnprogramming/comments/3opp5r/how_to_run_multiple_cpp_files_separately_in_same/
I do not want to change the IDE or compare it to other IDEs. What I am looking for, is the ability to execute one of hundreds of tiny programs that are in a well organized in an expandable file tree in C::B quickly and easily. If I put each C++ file with a main in it's own project I will have so many C::B projects that it will be unreasonable.
I do understand that C::B is not Eclipse and C++ is not Java, and that C::B is intended to have a single c++ file with a main function per project.
Any answers, and even very creative answers would be very appreciated! Scripts, settings, how to rewrite my code, whatever - if you have a suggestion I would love to hear it so I may consider it.
In the interest of full disclosure, currently I am keeping all my tiny programs in directories and use the O/S to drill through the directories and simply double click on the .cpp file which C::B opens. I am willing to dramatically modify my code to be able to achieve the objective.
Thanks for your time.

To compile and run a single main() file in a Code::Blocks project with multiple main() files:
In the "Projects" tab on the left, right-click on a file that you do not want to compile.
In the menu that appears, point to Options, and uncheck both Compile file and Link file.
This has to be done for all the files that you do not want to compile.
Now, when the project is built and run with F9, only the desired file will be compiled; the others will be ignored.
Note: It is not necessary to create a project in Code::Blocks to compile and run single file. To compile and run single files (without creating projects)
Just click on File -> Empty -> New file.
Save the file with .cpp extension anywhere (not in a project).
To compile and run the file, just press F9 or Build -> Build and run
However, such files (without projects) cannot be debugged. The most appropriate thing would be to just have a project with multiple main() files, as explained in the early part of this answer.

I've learned Java before, and am starting to learn C++ now.
When using Code::Blocks as my primary C++ IDE, I met the same problem as you. Although I found nothing useful on the Internet, I managed to figure it out on my own. Here is my solution.
In your Management panel, find your current project and right click, choose Close Project. (We won't use project to manage our code for this purpose.)
Still in the Management panel, find the Files tab, navigate to your working directory, right click on it and choose Make Root.
And we are done!
When you want to add a new code file, right click on your folder and choose New file..., enter your file name with the extension of .cpp. Then you can just use your C::B as before. Without the limit of project, C::B will just compile your current C++ file and run it on its own. Keyboard shortcuts F9 and the Run and Build button still works.
The only disadvantage is that you can see .exe and .o files in your file list, which is a little untidy. I'm still trying to find how to hide them in the list.
Hope this will help you.

How about using the precompiler? You can surround each main with:
#ifdef EXECUTE_EXAMPLE_1
int main() { return 0; } // example of one of the "mains" in one cpp
#endif
#ifdef EXECUTE_EXAMPLE_2
int main() { return 0; } // another "main" in an other cpp
#endif
#ifdef EXECUTE_EXAMPLE_3
int main() { return 0; } // yet another "main" somewhere else
#endif
And creating a header, included by all "mains" where you can define one to run:
#ifndef _EXECUTION_HEADER_H_
#define _EXECUTION_HEADER_H_
// Uncomment one and only one
#define EXECUTE_EXAMPLE_1
//#define EXECUTE_EXAMPLE_2
//#define EXECUTE_EXAMPLE_3
#endif // _EXECUTION_HEADER_H_
This could be a quick and dirty "build system" for your usecase.

I think this is what they were trying to accomplish.
No, you can't have two main files in the same Project, but you can have a lot of smaller project programs saved to a workspace which allows you to run and test them each individually.
https://www.youtube.com/watch?v=cHGIIp3rGO8

Related

Added C/C++ file to Eclipse Does not Compile

This has to be some kind of newbie question, but I have not been able to find any explaination.
I am running Ubuntu 18, and need to work with some C/C++ files. I've been using TI's CCS which is eclipse based on Windows for years.
I downloaded the Eclipse installer and ran it setting up for C/C++ developers.
https://www.eclipse.org/downloads/packages/installer
I created a new project. There were several different (unexplained) options such as CDT, MESON, MakeFile, ... I have tried several.
Creating a HelloWorld source file, it compiles and runs fine.
#include <stdio.h>
int main() {
puts("Hello World");
return 0;
}
Okay, so far...
Now I add a new source file. Called "OtherFile.c"
#include <stdio.h>
void OtherFunction() {
puts("Other Hello");
}
And of course, modify the original:
#include <stdio.h>
extern "C" void OtherFunction();
int main() {
puts("Hello World");
OtherFunction();
return 0;
}
When I try to build, it will not compile the new file. And (as expected) it tell me that "OtherFunction" is unresolved.
I have tried multiple project types (CDT, Meson, Makefile) even though there is no explanation of the differences. The newer file will not be compiled.
I tried changing the file extension from c to cpp and back. The newer file will not be compiled.
The TI version of CCS using Eclipse will include a source file when it's in the folder. However, in this environment, I cannot convince Eclipse to compile any other file than the one that was originally created by the new C/C++ project step.
And just as annoying is the fact that I can't right click either file and "Build Selected File". The menu option doesn't even appear.
This did not work for me:
eclipse c/c++ CDT build just one file
Can someone advice how to convince Eclipse to compile additional files?
TIA.
EDIT:
I can't upload here, so I just created something on GitHub.
These are two of the samples where I added a second file, and it ignores it.
https://github.com/scotty2541/EclipseExample
In all the other things I've done in Eclipse, it simply uses a default "recipe" like make does to compile the file.
If there is some way to manually tell Eclipse about it, that isn't explained anywhere I've been able to find. And seems to defeat the purpose of the IDE's behavior.
I was able to get it to behave as expected: By choosing a CDT managed build system, when adding a file to the project, it compiles it using the default recipe
Then, there is a setting which causes it to run the "builder" after a clean.
When I added the file as described originally, I also had to do a "clean" in order for the environment to include the additional file.

C++ Same include line in 2 files in the same folder: one works, another can't find the file

Windows 10
Eclipse IDE for C/C++ Developers
Version: Kepler Service Release 2
Build id: 20140224-0627
I'm trying to use imgui. Unfortunately, documentation is pretty shady about how to get it working.
So, in order to get it working, I think I need something called "glad". Whatever it is, the only source of it seems to be some shady-looking one-pager that generates the files for you (found a link to it here).
Anyway, I checked all the boxes I needed (copied from the screenshot from the provided link). I don't understand much about what it is (very roughly), I simply want to get imgui running (ha-ha on me, imgui also needs some other stuff scattered around internet, but it's my next problem, not current).
Anyway, in my new C++ project in eclipse I created a folder "include" and added its path into "C/C++ General -> Paths and Symbols". So when I write "#include "glad/glad.h" in my "test3.cpp" (file with main function, project called test3), I'm ok. But I can't build it because glad.c, which is located in the SAME folder as test3.cpp, has the identical include line, but it gives an error that it can't find it. Sounds like some nonsense to me.
#include "glad/glad.h"
#include <iostream>
using namespace std;
//for those who wanted to copy default hello world program
int main() {
cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
return 0;
}
How is this even possible? Looks like a total nonsense to me. They're in the same folder. Test3 sees the file, glad.c doesn't. I tried replacing "<>" in include in glad.c with quotes like in test3.c, same thing. One file works, another doesn't.
What can I do about it?
Eclipse separates the include paths for C and C++ files. If you have a program combining both C and C++ files, the correct include paths need to be set for both languages.
Navigate to the C/C++ General -> Paths and Symbols -> Includes tab. You will see both languages (and probably Assembly) listed under Languages. Pick the correct language or when adding the path, check the Add to all languages box.

Can I add googletest to existing visual c++ project? [duplicate]

I have a C++ project in Visual Studio, and have added another project exclusively for testing. Both of these projects are EXEs (console apps). So how do I use the first project inside the second?
Just to clarify, the question here would be somewhat self-evident if the first project was a library that one could simply include in the second project but, being an EXE, this is where the problem lies.
Per your comments, you have a C++ console application (MyApp) for which you have developed some application-specific classes that you want to unit-test with googletest in
Visual Studio. How?
As you say, if you wanted to unit-test a library the way to do it would be
obvious. You would:
1) Create a project to create a unit-testing application (UnitTest).
2) Configure the include-search directories so that the compiler can find the library's headers.
3) Configure the library-search directories so that the linker can find the library itself.
4) Add the library itself to the linker inputs.
5) Make the UnitTest project dependent on the library project, so that building UnitTest ensures MyApp is up-to-date.
6) Code the UnitTest app per googletest docs.
But since the classes you want to unit-test are specific to MyApp, you don't have any
library.
A drill-sergeant answer to that is: You don't have a library containing the classes you want to unit-test? So make one!
That way you use 3 projects:-
MyAppLib, generating library that contains all the functionality you want to unit-test.
MyApp, generating the same executable as at present, but linking MyAppLib
UnitTest, generating an executable that unit-tests MyAppLib, also linking MyAppLib
However if you don't like the drill-sergeant answer you can work around it.
From the usual build-system point of view (the one designed into Visual Studio),
the important output of the MyApp project is the build-target - the .exe.
The .obj files generated are just intermediate by-products. VS offers you no support
for treating these by-products as automatic linker inputs of a dependent project, and if a dependent project was also an .exe of the same sort - as it is your case - then such automatic linkage would be impossible anyhow because the main entry point would be multiply defined.
But from the unit-testing point of view it's the other way round. The .exe is of no interest, whereas (some of) the .obj files wholly or partly contain the implementations of the classes you want to unit test. In the text-book case where class foo is defined in foo.h and implemented in foo.cpp, the object file foo.obj is needed in the linkage of UnitTest.
For simplicity, assume that MyApp employs just one application-specific class foo,
defined in foo.h and implemented in foo.cpp. Then you have two options for building UnitTest.
a) You can add foo.cpp to the source files of UnitTest. Don't copy it of course. Just Add an existing item from the source folder of MyApp. Then you're done, but this
course has the downside that foo.cpp is exposed to untoward editing within
the UnitTest project.
b) You can treat foo.obj just like a static library required for the linkage of UnitTest and follow steps 1) - 6) above. This means in particular at step 3) that the {Debug|Release} build of UnitTest is configured with library-search directories that include \path\to\MyApp\{Debug|Release} (either in relative or absolute form).
In reality, for option b), there's very likely more than one .obj file from MyApp that you will have to link in UnitTest, and quite likely that their number will grow with time. Maintaining the right linkage of UnitTest could become a chore, and you might come to the conclusion that the drill-sergeant was right after all.
Depends. Google Test is (primarily) a Unit Testing framework (oversimplifying, testing classes). You can absolutely use is for other types of tests, but it doesn't have "built in" functionality for other types of testing, you'll have to write it yourself.
If you are trying to system test your executable, than you can run the process. I suggest using Boost.Process if you are using a multi-platform system or already have a boost dependency. Else, look here: launch an exe/process with stdin stdout and stderr?
The "tests" you write will call the executable, and can input stdin or stdout accordingly.
For example:
std::string path_to_exectuable = "thepath";
TEST(FooTester,CheckHelpScriptReturns0)
{
using bp =::boost::process;
std::vector<std::string> args; args.push_back("--help");
bp::context ctx;
ctx.stdout_behavior = bp::capture_stream();
bp::child c = bp::launch(exec, args, ctx);
bp::status s = c.wait();
ASSERT_TRUE(s.exited())<<"process didn't exit!";
ASSERT_EQ(s.exit_status(),0)<<"Help didn't return 0";
}
I was in a similar situation and I set this up in a way that effectively accomplishes the same goal of Mike Kinghan's answer as far as the compiler is concerned, but goes about it a different way from the user's perspective.
What I did was create a custom Configuration that I called "Testing". You create a new configuration by opening the project settings, choosing "Configuration Manager..." and selecting "New..." in the configuration selection box.
When prompted, I chose to copy the settings from the default "Debug" configuration, so that I can use the debugger with my tests just the same as if I was in the "Debug" configuration.
Under the new Testing configuration, I set the options for the compiler and linker to use google test as you normally would.
The important change in the properties is that I define a preprocessor variable which I have called "TESTING".
I rewrote my "main.cpp" to look something like this:
...
// includes
// functions
// whatever
...
#ifdef TESTING
#include <gtest/gtest.h>
#endif
int main(int argc, char **argv) {
#ifdef TESTING
::testing::InitGoogleTest(&argc, argv);
int val = RUN_ALL_TESTS();
getchar(); // not necessary, but keeps the console open
return val;
#endif
// rest of main() as normal...
}
What I'm trying to indicate is that I only changed a few lines right around where main is defined, I don't have to make gross changes spread throughout the file.
Now that this is all set up I simply made a new source folder for my tests, and create ".cpp" files in there. To avoid bloating the normal executable, I wrap these files with a check for the TESTING variable, so I have something like this:
tests/Test.cpp:
#ifdef TESTING
#include <gtest/gtest.h>
#include "my_class_header.h"
TEST(TestMyClass, test_something) {
// perform some test on class
}
#endif
I think these files still get "hit" by the compiler under Debug and Release configurations, so having a ton of these might slow down the build, but the Debug and Release objects wont get bloated with testing code.
The two takeaways are:
Using this method, the testing code is still organized separately from the application code, but it still resides in the same Visual Studio project, which may or may not be beneficial. Personally I like not having to manage/worry about a second project.
Like Mike Kinghan said, managing and linking .obj files yourself can become a chore, but by using this method, the default Visual Studio settings manage this for you.
One downside is that effectively redundant copies of all object files will get created in the "Testing" output directory. With more configuration, surely there must be a way to "share" the Debug object files, but I didn't have a reason to go that far.
This is a very simple method which may be a lot easier than refactoring your application into separate libraries and a main. I don't love using preprocessor wankery, but in this case it's fairly straightforward, not too much code bloat, and accomplishes exactly what it needs to. You could always trigger the tests another way, without using the preprocessor.
If you are not very rigid about having the tests in a different project, you can write the tests in your application project. Then just make the application execute the tests when receiving certain command line arguments, and execute the normal application logic otherwise, i.e.
int main(int argc, char* argv[])
{
if (argc >= 2 && std::string(argv[1]) == "--tests")
{
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
else
{
// Application logic goes here
}
}
TEST(ExampleTests, TestSQRTCalculation) // assuming all the right headers are included
{
EXPECT_NEAR(2.0, std::sqrt(4.0), 0.000001);
}
This avoids creating an unnecessary library for the sole purpose of testing, although you can still do it if it is correct structure-wise. The downside is that the testing code goes into the executable you are going to release. If you don't want that I guess you need an additional configuration which specifies a pre-processor directive to disable the tests.
Debugging the tests or running them automatically at post build is easy, simply by specifying "--tests" as debug args or at post build command line respectively.
If you want to test a console app you can run a test that opens a console window and run the exe file of the first app.
Then in your googletest catch the standard output from the exe you just ran.
[For more control over the first app you might need to have the first app parse arguments sent to it, e.g. some flags like -x or what ever you need.]
I have prepared a github repo including Visual Studio 2015 solution in parralel of Mike's "drill-sergeant" suggestion. You can use it directly without any additional requirement or dependency.
https://github.com/fuatcoskun/GoogleTestVS2015
I hope it helps...

Visual Studio console debugging wrong file

I have created an empty project and added two ( .cpp) items inside the project. Keep in mind that I am a beginner in C++ Visual Studio, so I have not used any code to somehow connect the two files.
Problem: The debugger was fine for debugging my first file, but when I open my second file and start running by clicking "Local Windows Debugger" (clicked when I was inside the second file), it will still keep on running the first file whether there was a bug or not.
When I looked at the debug window after I hit "Local Windows Debugger", I saw the file path pointing to the first file.
I have tried: Closing the first file completely, closing visual studio and opening my second file from my folder path, turning off the break-point in the first file and turning on in the second file.
I would like to know: How can I just run the second file? Do I have to use the command prompt to keep my two items in the empty project separate? I am using Windows 10 by the way.
I searched for my problem, but I had a hard time looking for a guide that gave a solution
Issue:
Dracep cannot debug one of two files they have. This is due to them having a main function definition in both files, causing the editor to favour one over the other.
Solution:
By having a third, dedicated entry point in your application (I.E. having a single point of entry you then include the other files), you can decide which file you are going to debug at any given time.
For example, having a file called main.cpp which then includes the other two files by using #include "filename.h".
From there you can include the file and make you code checks by calling the functions in that file rather than having a main and stepping down through it, causing long term issues of scalability.
Please see this question on separating your logic from your definitions, as the answer marked correct is the standard for most C++ projects you will find.
That way, you could do something like the following:
#include "File1.h"
#include "File2.h"
int main(int argc, char** argv)
{
File1Class file1Class;
File2Class file2Class;
//Do whatever tests you like with either.
}

netbeans can't find C++ header file in same directory

In one particular cpp file (abc.cpp), when I ask to navigate "to Declaration/Definition", it says "cannot open element "abc.h"". This functionality works for other header files. This in itself is not a big problem, but it also means that auto-complete and syntax highlighting doesn't work for this file.
Some extra info:
The header file is in the same directory as the cpp file and both are included in the active netbeans project
I was able to enter the header file name with auto-complete, i.e. #include "ab<ctrl-space>"
clicking the "Go to header/source" button works both ways for this cpp/h pair.
right-clicking on the class name in the header file, and then selecting "go to source" brings me to the cpp file, as usual.
in other cpp files the connection to the header file is working fine, as is autocomplete & syntax highlighting
netbeans has a green square in the top right of the header file window, indicating "no errors"
I have tried deleting my cache as explained here
I'm using netbeans v8.0.2 on OpenSuse 13.2
Here are some ideas:
Sometimes the Code Assistance is not as good for projects that Netbeans didn't create from scratch. If it is not a complicated Makefile, it might be worth it to create a new project with the C/C++ Application type and copy over and then add each source and header file.
The code assistance depends on analyzing he log from the build each time, so sometimes just rebuilding the project will fix the code assistance.
There are a number of options if you right click the project under the code assistance sub-menu.
Edit the Makefile to make sure this file is being compiled in the same way as the other files that work. It may be getting compiled with different options because it was added later and therefore not providing the same info for code assistance. You will need to rebuild after making these changes for them to have an effect.