unable to get text from combo box in gtk

[gomathibabu <gomsfoss au-kbc org>]

hai,
when i try to get selected text from combo box in gtk,it gives the error 
message.i pasted my coding and also error message this mail.please reply 
me as soon as possible.

Actually i wrote these statements in "clicked" event of the ok button.i 
declared combo box as global variable.

GtkWidget *Algorithm_combo;

void on_ok_button_clicked( )
{
gchar *algorithm;
algorithm=gtk_entry_get_text(GTK_ENTRY(GTK_COMBO(Algorithm_combo)->entry));
printf("%s",algorithm);
}


Error:

gomathi gomathi:~/primitive$ gcc primitive.c -o primitive `pkg-config 
--cflags --libs gtk+-2.0`
primitive.c: In function `on_ok_button_clicked':
primitive.c:73: warning: assignment discards qualifiers from pointer 
target type

please help me.
regards
gomathi