我写了这段代码,但似乎没有用。当我们输入d
时,它会对美元进行计算,但仍在进行(......什么?)。
你能在列表部分看到+ detect +,那部分是错误的吗?
String currency = sc.next();
char detect = currency.charAt(0);
switch (detect){
case 'D':
case 'd':
double dollar = (amount/18*10);
System.out.println(amount + " Turkish Lira(s) --> " + dollar + " Dollar");
case 'E':
case 'e':
double euro = (amount/23*10);
System.out.println(amount + " --> " + euro + " Euro");
case 'T':
case 't':
double lira = (amount);
System.out.println(amount + " --> " + lira+ " Lira(s)");
while (detect!='d'|| detect!='e' || detect!='t' || detect!='D'|| detect!='E' || detect!='T'){
System.out.println("Can u See " + detect + " In The List ?\n" + menucur);
currency = sc.next();
detect = currency.charAt(0);
}
}
答案 0 :(得分:4)
您需要在每个案例的末尾为switch语句添加break
。
请参阅http://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html
答案 1 :(得分:2)
在每个break
块中的每个系列语句的末尾添加case
,例如:
switch (detect){
case 'D':
case 'd':
double dollar = (amount/18*10);
System.out.println(amount + " Turkish Lira(s) --> " + dollar + " Dollar");
break; // <==== Add this
case 'E':
case 'e':
double euro = (amount/23*10);
System.out.println(amount + " --> " + euro + " Euro");
break; // <==== Again here
......等等。这告诉代码你不想继续进入下一个case
。
我建议您阅读一篇关于Java的好的入门读物。在评论中,MadProgrammer指出了一个特定于switch
,here的教程,但我会退后一步,对基础知识进行一些回顾。
为此,这是一个正确编写的switch
语句的例子:
// Assume `n` is an integer
switch (n) {
case 0:
case 1:
System.out.println("n is 0 or 1");
break;
case 2:
case 3:
case 4:
System.out.println("n is 2, 3, or 4");
break;
case 17:
System.out.println("n is 17");
break;
default:
System.out.println("n has some value other than 0, 1, 2, 3, 4, or 17");
break;
}
答案 2 :(得分:1)
Omar Jackman已经指出,缺少必要的beak
关键字。此外,要处理无效输入('D','d','E','e','T','t'以外的字母使用关键字default
):
switch(case)
case 'D':
case 'd':
double dollar = (amount/18*10);
System.out.println(amount + " Turkish Lira(s) --> " + dollar + " Dollar");
break;
case 'E':
case 'e':
double euro = (amount/23*10);
System.out.println(amount + " --> " + euro + " Euro")
break;
//.. rest of your code
// finally:
default: // <- handle invalid letter input
System.out.println("Invalid input");
break;
}