public?class?GoShopping?{
public?static?void?main(String[]?args)?{ double?sum=0; Scanner?input?=?new?Scanner(System.in); System.out.println("請輸入消費金額:"); double?money?=?input.nextDouble(); System.out.println("是否參加優惠活動:"); System.out.println("1:滿50元,加2元可換購百事可樂飲料壹瓶"); System.out.println("2:滿100元,加3元可換購500ml可樂壹瓶"); System.out.println("3:滿100元,加10元可換購5公斤面粉"); System.out.println("4:滿200元,加10元可換購1個蘇泊爾炒菜鍋"); System.out.println("5:滿200元,加20元可換購歐萊雅爽膚水壹瓶"); System.out.println("0:不換購"); System.out.println("請選擇:"); int?num?=?input.nextInt(); switch?(num)?{ case?0:System.out.println("不換購!");
break;
case?1:sum=money+2;
System.out.println("本次消費總金額:"+sum);
System.out.println("成功換購:百事可樂壹瓶!");
break;
case?2:sum=money+3;
System.out.println("本次消費總金額:"+sum);
System.out.println("成功換購:500ml可樂壹瓶!");
break;
case?3:sum=money+10;
System.out.println("本次消費總金額:"+sum);
System.out.println("成功換購:5公斤面粉!");
break;
case?4:sum=money+10;
System.out.println("本次消費總金額:"+sum);
System.out.println("成功換購:蘇泊爾炒菜鍋!");
break;
case?5:sum=money+20;
System.out.println("本次消費總金額:"+sum);
System.out.println("成功換購:歐萊雅爽膚水壹瓶!");
break;
default:System.out.println("操作有誤!請核對後輸入!");
break;
} }}
要定義壹個變量來接收消費總金額?不能直接寫成這樣:
System.out.println("本次消費總金額:"+money+2);
這樣只是把兩個數連接起來(+號起連接作用)?而不是求和