执行满足 2 个条件之一的 while 循环
Do while loop meeting one of 2 conditions
我正在尝试使用 do while 循环来确定用户是想将一只狗还是一只猫登记到 Java 中的犬舍系统中。这个想法是,他们在提示时输入 "dog" 或 "cat",任何输入都会导致错误,并且会再次提示他们输入文件名。
如果输入了"cat"或"dog",则等效文件将分配给程序(dogs.txt或cats.txt),然后系统将运行 并将该数据加载到程序中。
当前变量如下:
private String filename; // holds the name of the file
private Kennel kennel; // holds the kennel
private Scanner scan; // so we can read from keyboard
private String tempFileName;
private String dogsFile = "dogs.txt";
private String catsFile = "cats.txt";
以及导致问题的方法:
private KennelDemo() {
scan = new Scanner(System.in);
boolean fileNotCorrect = false;
System.out.print("Which animal are you looking to check into the kennel?: " + "\n");
System.out.println("Dog");
System.out.println("Cat");
tempFileName = scan.next();
do {
tempFileName.equals("dog");
filename = dogsFile;
fileNotCorrect = true;
/*tempFileName.equals("cat");
filename = catsFile;
fileNotCorrect = true;*/
}
while(fileNotCorrect = false);
System.out.println("That is not a valid filename, please enter either 'dog' or 'cat' in lowercase.");
下面是当您 运行 代码时打印的内容:
**********HELLO***********
Which animal are you looking to check into the kennel?:
Dog
Cat
cat
That is not a valid filename, please enter either 'dog' or 'cat' in lowercase.
Using file dogs.txt
无论输入什么,它都会为程序分配一个文件,然后继续加载程序。
我试过使用 catch { 但由于某种原因它不起作用,有人可以提供任何帮助吗?
谢谢!
这不是 do-while 的工作方式。你甚至都不检查。
使用这个:
do {
System.out.print("Which animal are you looking to check into the kennel?: " + "\n");
System.out.println("Dog");
System.out.println("Cat");
tempFileName = scan.next();
if(tempFileName.equals("dog") || tempFileName.equals("cat"))
{
filename = tempFileName.equals("dog") ? dogsFile : catsFile;
fileNotCorrect = true;
}else{
System.out.println("That is not a valid filename, please enter either 'dog' or 'cat' in lowercase.");
}
}
while(!fileNotCorrect);
我正在尝试使用 do while 循环来确定用户是想将一只狗还是一只猫登记到 Java 中的犬舍系统中。这个想法是,他们在提示时输入 "dog" 或 "cat",任何输入都会导致错误,并且会再次提示他们输入文件名。
如果输入了"cat"或"dog",则等效文件将分配给程序(dogs.txt或cats.txt),然后系统将运行 并将该数据加载到程序中。
当前变量如下:
private String filename; // holds the name of the file
private Kennel kennel; // holds the kennel
private Scanner scan; // so we can read from keyboard
private String tempFileName;
private String dogsFile = "dogs.txt";
private String catsFile = "cats.txt";
以及导致问题的方法:
private KennelDemo() {
scan = new Scanner(System.in);
boolean fileNotCorrect = false;
System.out.print("Which animal are you looking to check into the kennel?: " + "\n");
System.out.println("Dog");
System.out.println("Cat");
tempFileName = scan.next();
do {
tempFileName.equals("dog");
filename = dogsFile;
fileNotCorrect = true;
/*tempFileName.equals("cat");
filename = catsFile;
fileNotCorrect = true;*/
}
while(fileNotCorrect = false);
System.out.println("That is not a valid filename, please enter either 'dog' or 'cat' in lowercase.");
下面是当您 运行 代码时打印的内容:
**********HELLO***********
Which animal are you looking to check into the kennel?:
Dog
Cat
cat
That is not a valid filename, please enter either 'dog' or 'cat' in lowercase.
Using file dogs.txt
无论输入什么,它都会为程序分配一个文件,然后继续加载程序。
我试过使用 catch { 但由于某种原因它不起作用,有人可以提供任何帮助吗?
谢谢!
这不是 do-while 的工作方式。你甚至都不检查。
使用这个:
do {
System.out.print("Which animal are you looking to check into the kennel?: " + "\n");
System.out.println("Dog");
System.out.println("Cat");
tempFileName = scan.next();
if(tempFileName.equals("dog") || tempFileName.equals("cat"))
{
filename = tempFileName.equals("dog") ? dogsFile : catsFile;
fileNotCorrect = true;
}else{
System.out.println("That is not a valid filename, please enter either 'dog' or 'cat' in lowercase.");
}
}
while(!fileNotCorrect);