这是基于QT2.3.10的信号和槽的一个实例

				#include 				#include "counter.h"								Counter::Counter( QWidget *parent, const char *name ):QWidget( parent, name )								{								 counter = 0;				 				 label = new QLabel( "0", this );								 label->setAlignment( AlignVCenter | AlignHCenter );								 }								void Counter::IncCounter()								{				 char str[30];								 sprintf( str, "%d", ++counter );								 label->setText( str );								}								void Counter::DecCounter()				{				 char str[30];				 				 sprintf( str,"%d", --counter );								 label->setText( str );								}