Java 输出错误数据的双值排序

我在大学课程上遇到了一些问题。作业的最后一部分我也很沮丧，我认为容易的部分很快就变成了最难的部分。我被要求按距离对

.cvs

文件中的值进行排序（如

17.0123874627346,0.123761947

等）

这是我的代码：

public void sortDistance() {
    System.out.println("before distance sort");
    for (int k = 0; k < ntracks; k++) {
        System.out.println(tracks[k].getDistance());
    }
    for (int i = 0; i < ntracks; i++) {
        //find the index of the minimum position
        int index = i;
        //looping through array of distances
        for (int j = i + 1; j < ntracks; j++) {
            if  (tracks[index].getDistance() < tracks[j].getDistance())             
            {
                //position j is new mimum index
                index = j;
            }
        }
        //swap the two values around so smallest becomes track index
        Track smallerTrack  = tracks[index]; 
        tracks[index] = tracks[i]; 
        tracks[i] = smallerTrack;
    }
    System.out.println(" after distnace sort");
    for (int k = 0; k < ntracks; k++) {
        System.out.println(tracks[k].getDistance());
    }
}

public void sortDistance（）{
System.out.println（“距离排序前”）；
对于（int k=0；k

Float s[]={1,3,2}；

---

数组。排序

我认为没有必要实现您自己的排序逻辑，您可以使用提供的方法

Arrays.sort(tracks);

System.out.print(Arrays.toString(tracks));

TL:DR

• 对高精度浮点数使用BigDecimal
• 使用Compariable and Collections.sort（）进行排序

完整答案

看起来你有一个类，看起来有点像这样：

public class Track
    private float distance;
    public Track(float distance) {
        this.distance = distance;
    }
    public float getDistance() {
        return this.distance;
    }
}

public class Track
    private BigDecimal distance;
    public Track(String distance) {
        this.distance = new BigDecimal(distance);
    }
    public BigDecimal getDistance() {
        return this.distance;
    }
}

public class Track implements Comparable<Track> //Note we now implement an interface
    private float distance;
    public Track(float distance) {
        this.distance = distance;
    }
    public float getDistance() {
        return this.distance;
    }
    public int compareTo(Track track) { //And our implementation just delegates to the BigDecimal compareTo method
        return this.distance.compareTo(track.getDistance());
    }
}

如果是这样的话，那么我很想把它改大一点，然后使用

BigDecimal

BigDecimal

是一种设计用于在需要高精度时使用十进制数的对象。因为您的一个示例距离有13位小数，所以我将直接前往

BigDecimal

所以我把它改成这样：

public class Track
    private float distance;
    public Track(float distance) {
        this.distance = distance;
    }
    public float getDistance() {
        return this.distance;
    }
}

public class Track
    private BigDecimal distance;
    public Track(String distance) {
        this.distance = new BigDecimal(distance);
    }
    public BigDecimal getDistance() {
        return this.distance;
    }
}

public class Track implements Comparable<Track> //Note we now implement an interface
    private float distance;
    public Track(float distance) {
        this.distance = distance;
    }
    public float getDistance() {
        return this.distance;
    }
    public int compareTo(Track track) { //And our implementation just delegates to the BigDecimal compareTo method
        return this.distance.compareTo(track.getDistance());
    }
}

在这里，您可以依赖这样一个事实，

BigDecimal

实现了Comparable接口，因此它有一个

compareTo

方法。因此，您可以为Track实现

Comparable

，然后只

将
委托给
BigDecimal
上的compareTo方法。所以像这样：

public class Track
    private float distance;
    public Track(float distance) {
        this.distance = distance;
    }
    public float getDistance() {
        return this.distance;
    }
}

public class Track
    private BigDecimal distance;
    public Track(String distance) {
        this.distance = new BigDecimal(distance);
    }
    public BigDecimal getDistance() {
        return this.distance;
    }
}

public class Track implements Comparable<Track> //Note we now implement an interface
    private float distance;
    public Track(float distance) {
        this.distance = distance;
    }
    public float getDistance() {
        return this.distance;
    }
    public int compareTo(Track track) { //And our implementation just delegates to the BigDecimal compareTo method
        return this.distance.compareTo(track.getDistance());
    }
}

最后，我要说的是，我还没有运行任何这段代码，所以它可能无法编译

此外，以下是我提到的一些新概念的文档：





在java中，有一种内置方法，可用于排序。Java.util.array。它可以对基本类型数据进行排序。有关更多详细信息，请参阅oracle文档。