[英]I have a run time error in my JAVA program in my while loop
代碼可以編譯,但是當我執行它時,錯誤提示
“ java.util.NoSuchElementException”並突出顯示濕度= input.next();
示例輸出如下:
K-Nearest Neighbor Prediction Program:
The values you entered are: sunny cool high true
Comparring the values: sunny hot high false dist = 2 and play = no
Comparring the values: sunny hot high true dist = 1 and play = no
Comparring the values: overcast hot high false dist = 3 and play = yes
Comparring the values: rainy mild high false dist = 3 and play = yes
Comparring the values: rainy cool normal false dist = 3 and play = yes
這是我的代碼:
import java.util.Scanner;
public class lab2
{
public static void main (String [] args)
{
Scanner input = new Scanner ("data.txt");
System.out.println("The values you entered are : ");
String queryOutlook = "sunny";
String queryHumidity = "high";
String queryTemp = "cool";
String queryVerd = "true";
String outlook = null;
String humidity = null;
String temp = null;
String verd = null;
String play= null;
int distance = 0;
while(input.hasNext())
{
outlook = input.next();
***humidity = input.next();***
temp = input.next();
verd = input.next();
if (!outlook.equalsIgnoreCase(queryOutlook) )
distance++;
if (!humidity.equalsIgnoreCase(queryHumidity) )
distance++;
if (!temp.equalsIgnoreCase(queryTemp) )
distance++;
if (!verd.equalsIgnoreCase(queryVerd) )
distance++;
System.out.println(outlook + humidity + temp + verd + "\t" + play + distance);
同樣,該程序與K值最近鄰預測有關,這是自上一堂課以來我從未聽說過的。 任何幫助,將不勝感激!!!
while(input.hasNext()) {
outlook = input.next();
humidity = input.next();
temp = input.next();
verd = input.next();
您正在檢查輸入中是否有一個下一個元素,如果有,則得到四個下一個元素。 在獲取每一個之前,您應該檢查一下。
Scanner()的構造函數將java.io.File作為輸入。 您正在傳遞一個字符串。 因此,您的掃描器僅掃描字符串“ data.txt”尋找匹配項,而實際上並沒有打開該文件並對其進行掃描。
您需要執行以下操作來開始:
File f = new File("data.txt");
Scanner input = new Scanner(f);
... // and so on
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