Question

这两个问题都在getCity方法中，在注释中标记。任何帮助都会很棒，如果您在阅读时看到任何其他错误，我会接受任何帮助。

//DO NOT ALTER THE MAIN METHOD
public static void main(String[] args) {
    //determine input file
    String fileName = "coven_consulting.txt";
    //print method to output breakdown
    printReport( fileName );
}

/* printReport - take the file name, open the file, read and process data, print out report
 * input: String fileName - the name of the file containing the data
 * returns: nothing
 */
private static void printReport( String fileName ) {
    //implement this method
}

/* getCity - ask the user for a city, loop unitl the user gives you a valid one
 * input: none
 * returns: String - the name of the validated city
 */
@SuppressWarnings("empty-statement")
private static String getCity() {
//implement this method, change the return statement to suit your needs
    Scanner keyboard = new Scanner (System.in);
    String input;
    String city = "";

    do {
        System.out.print("Which city do you want a report for?");
        input = keyboard.next();

        if (checkValidCity(input) == true ) 
        input = city;
        while (checkValidCity(input) == false);
            System.out.print("Not a city we consult in, try another...");     
    }    //Error: says while expected
    return city;  //Error: says illegal start to expression
}  

private static boolean checkValidCity(String input) {
    //implement this method, change the return statement to suit your needs
    boolean result;
    if (input.equalsIgnoreCase ("Uberwald") || 
        (input.equalsIgnoreCase ("Pseudopolis")) ||
        (input.equalsIgnoreCase ("Quirm")) || 
        (input.equalsIgnoreCase ("AnkhMorpork")))
        result = true;
    else
        result = false;
    return result;
}

Answer 1

do {
    // code
}

不是有效的表达。

您正在寻找do {} while (booleanExpression);

您的第二个错误是由于第一个错误。

while (checkValidCity(input) == false);

最后你不需要分号，否则什么都不会发生。

Answer 2

将您的代码更改为以下。执行for while的时间为{// this} while（condition）

  do {
            System.out.print("Which city do you want a report for?");
            input = keyboard.next();



            if (checkValidCity(input) == true ) 
            input = city;


        }     while (checkValidCity(input) == false)

Answer 3

更改语法。 while应该在do的正文之外。

正确的语法是：

do {
   // code, bla, blaaa
} while (condition);

所以你的代码应该是这样的：

do {
    System.out.print("Which city do you want a report for?");
    input = keyboard.next();
    if (checkValidCity(input)) {
        input = city;
    }
    System.out.print("Not a city we consult in, try another...");     
} while (!checkValidCity(input));

请给我一个提示，请在使用if-else声明时，请不要忘记括号{}。

我方法中的错误

3 个答案: