Question

我有这个类（有setter，getters和一个方法），无限期地向用户询问一个数字，直到他输入-1。我从主要方法和类本身调用了扫描程序方法，有一种方法只能从主方法调用扫描程序方法一次，并将输入应用于类每次需要它？我非常感谢你的帮助。如果不清楚，请与我联系。

这是“类别代码”：

public class calculation { int current = 0; int maxNum = 0; int minNum; int counter=0; float sum = 0; float avg; Scanner scan = new Scanner(System.in); public void setMin(int min){ this.minNum = min; } public int getMin(){ return minNum; } public void setMax(int max){ this.maxNum = max; } public void setSum(float sum){ this.sum += sum; } public void minMax(int current){ setMin(current); while(current!=-1){ setSum(current);; if(current>getMin()){ setMax(current); }else if(current<getMin()){ setMin(current);; } current = scan.nextInt(); counter++; } System.out.println("The smallest number you entered was: \n" + minNum); System.out.println("The biggest number you entered was: \n" + maxNum); System.out.println("The sum of all those numbers is: \n" + sum); System.out.println("The avarege number is: \n" + (sum/counter)); } }

这是主要的方法代码：

public class minusOne { public static void main(String[] args) { Scanner scan = new Scanner(System.in); calculation cal1 = new calculation(); System.out.println("Type numbers at will, when finish, type -1 and press enter"); cal1.minMax(scan.nextInt()); scan.close(); } }

Answer 1

据我了解，您不希望两次致电new Scanner(System.in);

为避免这种情况，您可以在课堂计算中简单地写： Scanner scan;

添加构造函数：

public calculation(Scanner sc){
    scan = sc;
}

当然，在主要方法中你应该写： new calculation(scan)

我希望我回答你的问题

注意：在Java中，您的类名称应以大写字母开头，应为Calculation

Answer 2

你有一些替代方法，你可以让你的Calculator类带有一个构造函数，它将Scanner作为一个参数，然后将它存储在一个字段中，或者你可以在Calculator类和main中有一个公共字段。你得到扫描仪只会影响这个字段（但它应该是私有的，你可以通过getter和setter方法改变它。）

 /* This is the first option*/
public class Calculation {

    int current = 0;
    int maxNum = 0;
    int minNum;
    int counter=0;
    float sum = 0;
    float avg;

private Scanner scan;

public Calculation(Scanner scan){
     this.scan = scan;
}
public int setCurrent(int current){
   this.current = current;
   return current;
}

public void setMin(int min){
    this.minNum = min;
}

public int getMin(){
    return minNum;
}

public void setMax(int max){
     this.maxNum = max;
}

public void setSum(float sum){
     this.sum += sum;
}

public void minMax(int current){
    setMin(current);
    while(current!=-1){
        setSum(current);;
        if(current>getMin()){
            setMax(current);
        }else if(current<getMin()){
            setMin(current);;
        }

    current = setCurrent(current);;

    counter++;
    }
    System.out.println("The smallest number you entered was: \n" + minNum);
    System.out.println("The biggest number you entered was: \n" + maxNum);
    System.out.println("The sum of all those numbers is: \n" + sum);
    System.out.println("The avarege number is: \n" + (sum/counter));

   }
}

/* Second option */
  public static void main(String[] args) {

    Scanner scan = new Scanner(System.in);


    calculation cal1 = new calculation();
    //if the field scan in Calculation is public
    cal1.scan = scan;
    //if it is private
    cal1.setScan(scan);
    System.out.println("Type numbers at will, when finish, type -1 and press    enter");
    cal1.minMax(scan.nextInt());

    scan.close();

}

仅使用主方法的扫描仪

2 个答案: