How do I set the icon name in the taskbar in Ubuntu?

Question

I am new to this part of coding, so here i am trying to name the icon which is popped in the taskbar when we open an application. I have created test.c file for testing but it is not giving me the output what i want, it's showing "unknown" for the icon name in the taskbar. If anyone could help in this, that would be a great help. I've attached the code below and thanks in advance.

#include </usr/include/X11/Xlib.h>
#include </usr/include/X11/Xatom.h>

bool quited = false;

void on_delete(Display * display, Window window)
{
    XDestroyWindow(display, window);
    quited = true;
}

int main(int argc, char *argv[])
{
    Display * display = XOpenDisplay(NULL);
    if (NULL == display) {
        fprintf(stderr, "Failed to initialize display");
        return EXIT_FAILURE;
    }

    Window root = DefaultRootWindow(display);
    if (None == root) {
        fprintf(stderr, "No root window found");
        XCloseDisplay(display);
        return EXIT_FAILURE;
    }

    Window window = XCreateSimpleWindow(display, root, 0, 0, 800, 600, 0, 0, 0xffffffff);
    if (None == window) {
        fprintf(stderr, "Failed to create window");
        XCloseDisplay(display);
        return EXIT_FAILURE;
    }

    XStoreName(display, window, "Test-Application");

    Atom net_wm_name = XInternAtom(display, "_NET_WM_NAME", False);
    XChangeProperty(display, window, net_wm_name, XA_STRING, 8,
                    PropModeReplace, (unsigned char *)"Testing", strlen("Testing"));

    XMapWindow(display, window);

    Atom wm_delete_window = XInternAtom(display, "WM_DELETE_WINDOW", False);
    XSetWMProtocols(display, window, &wm_delete_window, 1);

    XEvent event;
    while (!quited) {
        XNextEvent(display, &event);

        switch(event.type) {
        case ClientMessage:
            if(event.xclient.data.l[0] == wm_delete_window) {
                on_delete(event.xclient.display, event.xclient.window);
            }
            break;
        }
    }

    XCloseDisplay(display);

    return 0;
}