从文件/数组中读取。没有价值。没有错误

Any ideas what I am missing here? I am reading from a file array. The values in the text file don't get stored and there is no output. All I get is "names and totals" but no values.

我在这里缺少什么想法?我正在从文件数组中读取。文本文件中的值不会存储,也没有输出。我得到的只是“名字和总数”,但没有价值。

I don't know.

我不知道。

private int[] totals;
private String[] names;
private String[] list;

private int count;


public void readData() throws IOException {

    BufferedReader input = new BufferedReader(new FileReader("cookies.txt"));

    //create the arrays
    totals = new int[count];
    names = new String[count];
    list = new String[count];

    //read in each pair of values
    String quantityString = input.readLine();
    for (int i = 0; i < count; i++) {
        names[i] = input.readLine();
        list[i] = input.readLine();
        quantityString = input.readLine();
        totals[i] = Integer.parseInt(quantityString);
    }

}

public void display() {
    System.out.println("names           totals")
    for (int i = 0; i < count; i++)
        System.out.println(list[i] + "        \t " + names[i] + "        \t" + totals[i]);
}

//called to compute and print the result
public void printResults() {

    //find the best teacher
    int maxIndex = 0;
    int maxValue = 0;

    //for each record stores
    for (int i = 0; i < count; i++) {
        //if we have a new MAX value so far, update variables
        if (maxValue < totals[i]) {
            maxValue = totals[i];
            maxIndex = i;
        }
    }
}

1 个解决方案

#1

You never give the variable count a value, so it initialized to 0 by Java. This means that your arrays are of size 0 also.

你永远不会给变量计数一个值,所以它被Java初始化为0。这意味着您的数组大小也为0。

So since count is zero, you never read anything from the file, which is why nothing is stored in your arrays and also why nothing is printed out.

因此,由于count为零,你永远不会从文件中读取任何内容,这就是为什么没有任何内容存储在数组中以及为什么没有打印出来的原因。

Example: Reading a File line-by-line

示例:逐行读取文件

// create temporary variable to hold what is being read from the file
String line = "";

// when you don't know how many things you have to read in use a List
// which will dynamically grow in size for you
List<String> names = new ArrayList<String>();
List<Integer> values = new ArrayList<Integer>();

// create a Reader, to read from a file
BufferedReader input = new BufferedReader(new FileReader("cookies.txt"));

// read a full line, this means if you line is 'Smith 36' 
// you read both of these values together
while((line = input.readLine()) != null) 
{
   // break 'Smith 36' into an array ['Smith', '36']
   String[] nameAndValue = line.split("\\s+"); 

   names.add(nameAndValue[0]);                   // names.add('Smith')
   values.add(Integer.parseInt(nameAndValue[1]); // values.add(36);
}

#1