阅读名称和数字混合的文件，并将它们放入不同的数组中

Question

我在java简介类中，我知道这个问题对您来说可能非常简单，但我确实需要帮助。 因此，我试图从包含名称和收入的文件中读取，并且我想将它们读入不同的数组中。

import java.io.*; 
import java.util.Scanner; 
public class caltax 
{ 
    public static void main (String[] args) 
    { 
    String lname[] = new String [12]; 
    String fname[] = new String [12]; 
    Double income[] = new Double [12]; 
    double sincome=0.0; 
    int i, count=1; 

try 
{ 
    Scanner infile = new Scanner (new FileInputStream("family.dat")); 

    while (infile.hasNextLine()) 
    { 

    lname[12] = infile.next(); 
    fname[12] = infile.next(); 
    income[12] = infile.nextDouble(); 

    }//while 

    infile.close(); 

}//try 
catch (Exception e) 
{ 
    System.out.println("Check the file"); 
}//catch block  

for(i=0;i<12;i++) 
{ 
if (lname[i].equals(lname[i+1])) 
{ 
    count++; 
    sincome += income[i]; 

    //object t is created and constrctor is called 
    taxcalculation t = new taxcalculation (count, lname, fname, sincome); 
    t.taxowned(); 
}//if 

}//for 
}//main 
}//class 

Answer 1

你几乎在那里。我想这仅仅是错字LNAME []，FNAME []，收入[]中，虽然：

while (infile.hasNextLine()) 
{ 
lname[12] = infile.next(); 
fname[12] = infile.next(); 
income[12] = infile.nextDouble(); 

} //而

假设你只需要从文件中第一次12行，它必须看起来像：

int lineIdx =0; 
while (infile.hasNextLine() && lineIdx < 12) 
{ 
lname[lineIdx] = infile.next(); 
fname[lineIdx] = infile.next(); 
income[lineIdx] = infile.nextDouble(); 
lineIdx++; 
}//while 

---

更新时间：WOR王逻辑（请阅读代码中的评论）...抱歉延迟。

 // 1. Define two arrays 
    String[] families = null; 
    double[] taxes = null; 

    // 2. Read file: 
    while (infile.hasNextLine()) { 
     String personLastName = infile.next(); 
     // skip first name 
     infile.next(); 
     double personTax = infile.nextDouble(); 
     // add person data 
     if (null == families) { 
      // create array for 
      families = new String[] { personLastName }; 
      taxes = new double[] { personTax }; 
     } else { 
      boolean familyExists = false; 
      // check existing families 
      for (int i = 0; i < families.length; i++) { 
       if (personLastName.equals(families[i])) { 
        // got it! add personTax to family owed taxes 
        taxes[i] += personTax; 
        familyExists = true; 
        break; 
       } 
      } 
      if (!familyExists) { 
       // Extend arrays to put new family 
       // create temp arrays with size+1 
       String[] tmpFamilies = new String[families.length + 1]; 
       double[] tmpTaxes = new double[taxes.length + 1]; 
       System.arraycopy(families, 0, tmpFamilies, 0, families.length); 
       System.arraycopy(taxes, 0, tmpTaxes, 0, taxes.length); 
       // set new last elements data 
       tmpFamilies[tmpFamilies.length - 1] = personLastName; 
       tmpTaxes[tmpTaxes.length - 1] = personTax; 
       // replace families and taxes with newly created tmp arrays 
       families = tmpFamilies; 
       taxes = tmpTaxes; 
      } 
     } 
    }// while 
    // Print results 
    System.out.println("Found " + families.length + " families and their taxes");  
    for (int i=0;i < families.length; i++) 
    { 
     System.out.println("family " + families[i] + " owes $" + taxes[i]); 
    } 

Answer 2

为什么要将它们读入不同的数组？这是你的任务要求吗？更好的解决方案是创建一个包含Employee等属性的对象，然后将每个Employee添加到List<Employee>

如果您问的是如何迭代添加项目到您的数组，您需要一个索引，从0开始，结束于array.length - 1.