how to compile a C code to call an octave function and make the GUI using GTK+2

i am trying to call a octave function from C code but the problem is that when why run this command in octave mkoctfile --mex addition_GUI.c error occurs addition_GUI.c:1:20: fatal error: gtk/gtk.h: No such file or directory compilation terminated.

#include<gtk/gtk.h>
#include "mex.h"

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
mxArray *in[2], *out[1];

in[0] = mxCreateDoubleScalar(1);
in[1] = mxCreateDoubleScalar(2);

mexCallMATLAB(1, out, 2, in, "addition");
mexCallMATLAB(0, NULL, 1, out, "disp");

mxDestroyArray(in[0]);
mxDestroyArray(in[1]);
mxDestroyArray(out[0]);
}
void static call(GtkWidget *widget,gpointer data)
{
g_print("\n%s\n",gtk_entry_get_text(GTK_ENTRY(data)));
gint a=3;
gint b=2;
gint x;
x=a+b;
char y[4]; 
    sprintf(y, "%d", x);
    gtk_entry_set_text(GTK_ENTRY(data),y); 
}

    int main(int agrc, char *agrv[])

{
gtk_init(&agrc,&agrv);
GtkWidget *entry,*window,*button,*hbox;

window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
g_signal_connect(window,"delete-event",G_CALLBACK(gtk_main_quit),NULL);

hbox=gtk_hbox_new(0,0);
gtk_container_add(GTK_CONTAINER(window),hbox);
button=gtk_button_new_with_mnemonic("ADD");
entry=gtk_entry_new();
const char* sum="3+2";
gtk_entry_set_text(GTK_ENTRY(entry),sum); 
g_signal_connect(button,"clicked",G_CALLBACK(call),entry);
g_signal_connect(entry,"activate",G_CALLBACK(call),entry);



gtk_box_pack_start(GTK_BOX(hbox),button,0,0,0);

gtk_box_pack_start(GTK_BOX(hbox),entry,0,0,0);

gtk_widget_show_all(window);
gtk_main();
return 0;

}