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Question

更新：我已经尝试将getCalcMean（）和calcMean；我理解这个错误的含义，但我不知道如何修复它，因为最终结果需要是double，我认为java可以计算double和int并得到double。我做错了什么？

我正在计算键入999后的总数平均值，但它一直显示为0，我不知道为什么。

有人能告诉我如何让我的getCalcMean（）方法将平均值显示为numTotal/count吗？

---班级计划---

public static void main(String[] args) {
    Scanner kb = new Scanner(System.in);
    int num = 0;
    int count = 1;
    Math math1 = new Math(num, count);
    while (num != 999) {
        num = kb.nextInt();
        if (num != 999) {
            math1.adder(num);
            count ++;
            System.out.println("Total till now:" + math1.getNumTotal());
        }
    }
    math1.setCount(count);
    System.out.println(math1.getNumTotal());
    System.out.println(math1.calcMean(math1.getCalcMean()));
    //System.out.println(math1.getNum());
    kb.close();
    /*Scanner kb = new Scanner(System.in);
    String input = kb.nextLine();
    Scanner scn = new Scanner(input);
    int num = scn.nextInt();
    Math math1 = new Math(num,0);
    while(num != 999){
        math1.adder(num);
        input = kb.nextLine();
    }

    System.out.println(math1.getNumTotal());*/
} //main

}

----数学课----

public class Math {

private int num;
private int numTotal;
private double mean;
private int count;

/*public Math(int num, int numTotal){
this.num = num;
}*/

public Math(int num, int count) {
    this.num = num;
    this.count = count;
}

//get//
public int getNum(){
    return this.num;
}

public int getNumTotal(){
    return this.numTotal;
}

public double getCalcMean(){
    return this.mean;
}

//set//

public void setNumTotal(int value){
    this.numTotal = value;
}

public void setNum(int value){
    this.num = value;
}

public void setCalcMean(double value){
    this.mean = value;
}

public void setCount(int value){
    this.count = value;
}
//other
/*public void adder(int num){
numTotal = numTotal + num;
}*/

public void adder(int num) {
    this.num = num;
    numTotal = numTotal + this.num;
}
//added after//
public double calcMean(int num){
    this.numTotal = numTotal;
    mean = numTotal / this.count;
    return mean;
}

}

Answer 1

代码中的< li> counter 没有意义，因为您从未将它传递给Math对象。 < Li > < code > math 1 . getcalcmean()将返回Math对象中的< code>mean，但< code>mean尚未计算。

建议：

1. 为Math类中的计数器添加getter和setter
2. 计算getCalcMean（）方法中的平均值

请参阅下面的代码。我假设您使用999作为结束标志，所以没有考虑它。计数器初始化为0。

import java.util.Scanner;

public class Program {
public static void main(String[] args) {
    Scanner kb = new Scanner(System.in);
    int num = 0;
    int counter = 0;
    Math math1 = new Math(num, counter);
    while (num != 999) {
        num = kb.nextInt();
        if (num != 999) {
            math1.adder(num);
            counter ++;
            math1.setCounter(counter);
            System.out.println("Total till now:" + math1.getNumTotal());
        }
    }
    System.out.println(math1.getNumTotal());
    System.out.println(math1.getCalcMean());
    //System.out.println(math1.getNum());
    kb.close();
    /*Scanner kb = new Scanner(System.in);
    String input = kb.nextLine();
    Scanner scn = new Scanner(input);
    int num = scn.nextInt();
    Math math1 = new Math(num,0);
    while(num != 999){
        math1.adder(num);
        input = kb.nextLine();
    }

    System.out.println(math1.getNumTotal());*/
} //main
}

还有数学课。

public class Math {

private int num;
private int numTotal;
private int mean;
private int counter;

/*public Math(int num, int numTotal){
this.num = num;
}*/

public Math(int num, int counter) {
    this.num = num;
    this.counter = counter;
}

//get//
public int getNum(){
    return this.num;
}

public int getNumTotal(){
    return this.numTotal;
}

public int getCalcMean(){
    mean = numTotal / this.counter;
    return mean;
}

public int getCounter(){
    return this.counter;
}

//set//

public void setNumTotal(int value){
    this.numTotal = value;
}

public void setNum(int value){
    this.num = value;
}

public void setCalcMean(int value){
    this.mean = value;
}

public void setCounter(int counter){
    this.counter = counter;
}

//other
/*public void adder(int num){
numTotal = numTotal + num;
}*/

public void adder(int num) {
    this.num = num;
    numTotal = numTotal + this.num;
}
//added after//
public void calcMean(int num){
    mean = numTotal / this.counter;
}
}