我有超過1000個名稱的文件,它還包括性別以及有多少人擁有該名稱。如何打印來自增強for循環的前10行
例如
薩拉˚F2000
我試圖打印從創建的第10行我的循環,但由於某種原因,我的嘗試只打印最後一行10倍。
import java.util.*;
import java.io.*;
import java.util.Collections;
public class NameYear
{
private String year;
ArrayList<OneName> oneName = new ArrayList<OneName>();
public NameYear(String year)
{
String line = "";
String Top = "";
Scanner sc = null;
try
{
sc = new Scanner(new File
("/home/mathcs/courses/cs225/koch/names/yob"+year+".txt"));
}
catch (Exception e)
{
System.out.println("Error Year should be between 1880 and 2013 not "+ year);
System.exit(1);
}
while(sc.hasNextLine())
{
// read a line from the input file via sc into line
line = sc.nextLine();
StringTokenizer stk = new StringTokenizer(line, ",");
String name = stk.nextToken();
char sex = stk.nextToken().charAt(0);
int count = Integer.parseInt(stk.nextToken());
OneName list = new OneName(name, sex, count);
oneName.add(list);
}
for (int i = 0 ; i < 10; i++)
{
System.out.println(descending());
}
public String descending()
{
String x = "";
Collections.sort(oneName, new OneNameCountCompare());
for(OneName b: oneName)
{
x = b.toString();
}
return x;
OneName文件
public class OneName
{
private String Name;
private char Sex;
private int Count;
public OneName(String name, char sex, int count)
{
Name = name;
Sex = sex;
Count = count;
}
public String getName()
{
return Name;
}
public char getSex()
{
return Sex;
}
public int getCount()
{
return Count;
}
public void setName(String name)
{
if (name.length() < 1)
{
throw new NullPointerException("Baby name is missing");
}
Name = name;
}
private char M;
private char F;
public void setSex(char sex)
{
if(sex != M)
{
if(sex != F)
{
throw new IllegalArgumentException("Sex has to be M or F");
}
}
Sex = sex;
}
public void setCount(int count)
{
if(count < 0)
{
throw new IllegalArgumentException("Count cant be negative");
}
Count = count;
}
public String toString()
{
return String.format("%s %c %d", Name, Sex, Count);
}
}
OneNameCount
import java.util.Comparator;
import java.util.Collections;
public class OneNameCountCompare implements Comparator<OneName>
{
public int compare(OneName b1, OneName b2)
{
if(b1.getCount() <b2.getCount())
{
return 1;
}
else
{
return -1;
}
}
}
主程序
import java.io.*;
import java.util.*;
public class TopNames
{
public static void main(String args[])
{
String line = ""; // string var to hold entire line
if (args.length < 1)
{
System.out.println("\nYou forgot to put a Year on the command line.");
System.exit(1);
};
String inFile = args[0]; // file name off command line
String year = inFile;
NameYear list = new NameYear(year);
}
}
首先拋出非法參數異常,而不是在NPE#OneName setname可以。 其次你爲什麼要整理它?只要顯示它,就像你想看到你輸入的前10個一樣。 – StackFlowed 2014-10-02 12:27:11
用調試器瀏覽代碼並觀察會發生什麼。特別要注意你從'降序'返回的內容。 – 2014-10-02 12:28:25
你的代碼亂七八糟。這是什麼原因 - System.out.println(descending()); ? – 2014-10-02 12:29:01