java - 找不到 java.util.Scanner 的符号 hasNextInt

Question

我正在自学 Java，并且遇到了一个我想解决的问题。这是问题所在:

Write a class named Calculator with a method int sum(String s). String s contains a set of integers separated by white space (blanks, tabs, or newlines). Return the sum of the integers.

You can use a Scanner object to solve this problem. Create a new Scanner(s) and store it in a variable, say in. Then, use in.hasNextInt() to control a while loop. Each iteration of the while loop uses in.nextInt() to get the next integer from the String s. Accumulate this integer into a variable and return that variable when the loop exits.

You may use a main method to test your method by creating an instance of the Calculator class and calling sum(…) with several combinations of values using that instance.

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到目前为止我的代码是

import java.util.Scanner;

public class calculator{
    public int sum(String s){
        new Scanner(s);
        String in = s;
        while (s.hasNextInt()) {
            s = in.nextInt();
        }
        return(0);
    }
}

我还没有完成类(class)，但我收到一个错误提示

cannot find symbol : method hasNextInt()

为什么？我不太确定从这一点开始该做什么，所以我应该做什么？ s是否正确存储到in中？

Answer 1

你的变量声明，

new Scanner(s);
String in = s;

完全错误。您必须将扫描仪存储在变量中。这意味着:

Scanner myScanner = new Scanner(s);

然后

while (myScanner.hasNextInt())