gtkmm entry holds gibberish

SC_DStwo_Master

I'm trying to make a simple program that does input validation on the text that the user inputs so that you cannot enter ‘a’. Here's the code:

#include <gtkmm/application.h>
#include <gtkmm/window.h>
#include <gtkmm/entry.h>
#include <cstring>
#include <iostream>

class entry
{
	protected:
		Gtk::Entry myEntry;
	public:
		void changed()
		{
			Glib::ustring text = myEntry.get_text();
			int length = text.length();
			char newText[length];
			if (text[length-1]=='a')
			{
				for (int i{}, e{}; i<length; ++i, ++e)
				{
					if (i==length-1) { --e; continue; }
					newText[e]=text[i];
					std::cout << text[i] << std::endl;
				}
			}
			Glib::ustring newTextConverted(newText);
			myEntry.set_text(newTextConverted);
		}
		entry(Gtk::Window& window)
		{
			myEntry.signal_changed().connect(sigc::mem_fun(this,&entry::changed));
			window.add(myEntry);
			myEntry.show();
		}
};

int main(int argc, char** argv)
{
	Glib::RefPtr<Gtk::Application> app = Gtk::Application::create(argc,argv,"org.nyap.test.base");

	Gtk::Window window;
	window.set_default_size(200,200);
	
	entry textt(window);

	return app->run(window);
}

When I run the program, I get the entry box, but when I try entering something, I get a segfault. I tried adding this:

void changed()
{
	Glib::ustring text = myEntry.get_text();
	//Here!
	std::cout << text.c_str() << std::endl;
	int length = text.length();
	char newText[length];
	if (text[length-1]=='a')
	{
		for (int i{}, e{}; i<length; ++i, ++e)
		{
			if (i==length-1) { --e; continue; }
			newText[e]=text[i];
			std::cout << text[i] << std::endl;
		}
	}
	Glib::ustring newTextConverted(newText);
	myEntry.set_text(newTextConverted);
}

And when I enter something, I get a load of gibberish in the terminal, followed by the segfault. What am I doing wrong

Last edited by SC_DStwo_Master (Oct. 8, 2016 17:38:36)

MegaApuTurkUltra

Why not just use ustring::find() and ustring::replace()?

lugga

Just thought that maybe this is the problem.

if (text[length-1]=='a')
{
	for (int i{}, e{}; i<length; ++i, ++e)
	{
		if (i==length-1) { --e; continue; }
		newText[e]=text[i];
		std::cout << text[i] << std::endl;
	}
}

Shouldn't the

for (int i{}, e{}; i<length; ++i, ++e)

be

for (int i{}, e{}; i<length-1; ++i, ++e)

To see if an the text is being accessed out of bounds.

Just to warn you, I might be wrong but it's worth a try!

SC_DStwo_Master

lugga wrote:
Just thought that maybe this is the problem.
if (text[length-1]=='a')
{
	for (int i{}, e{}; i<length; ++i, ++e)
	{
		if (i==length-1) { --e; continue; }
		newText[e]=text[i];
		std::cout << text[i] << std::endl;
	}
}
Shouldn't the
for (int i{}, e{}; i<length; ++i, ++e)
be
for (int i{}, e{}; i<length-1; ++i, ++e)
To see if an the text is being accessed out of bounds.

Just to warn you, I might be wrong but it's worth a try!

nope

SC_DStwo_Master

turns out there's a function just for this called “erase”
it works fine now
thanks for the help though

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