一个消除if语句的例子

// 一个按钮点击事件，判断点击按钮是那一个显示出他的信息

- (IBAction)buttonPressed:(id)sender {
    if (sender == self.leftButton) {
        NSLog(@"%@", self.leftButton.currentTitle);
        self.labelMessage.text = self.leftButton.currentTitle;
    }
    else{
        NSLog(@"%@", self.rightButton.currentTitle);
        self.labelMessage.text = self.rightButton.currentTitle;
    }
}

- (IBAction)buttonPressed:(id)sender {
    UIButton *button = (UIButton*)sender;
    NSLog(button.currentTitle);
    self.labelMessage.text = button.currentTitle;
}