Question

我正在编写一个包含文本文件的类程序，其中包含以下内容：

1 3 2 4 3 2

1 2 2 7 3 2

添加

我想将前两行中的每一行复制到单独的多项式中（LinkedLists）。我可以让扫描器对整个文件中的所有整数进行标记，并将所有内容复制到一个多项式中，但我想在第一行中读取，停止，然后将第二行整数复制到单独的多项式中。我不知道如何在每行结束时停止扫描仪。有什么建议吗？

这是我的代码（相关部分位于底部的主要部分）。

public class Polynomial {

private Term head;  //header before first item
private Term tail;  //trailer after last item
private int size; // number of elements in Polynomial

//constructor of empty Polynomial

public Polynomial(){
    head = new Term();
    tail = new Term();
    head.next = tail;
    tail.prev = head;       
} // end empty Polynomial constructor


//Term class
private static class Term {
    private int exp;
    private double coeff;
    private Term next;
    private Term prev;

    //constructor of empty Term
    public Term() {
        this.exp = -1;
        this.coeff = 0.0;
    }// end empty Term constructor

    //constructor of term with exponent and coefficient
    public Term(int e, double c){
        this.exp = e;
        this.coeff = c; 
    }//end constructor of term with exponent and coefficient

    //getters of exponent and coefficient
    public int getExp() {return exp;}
    public double getCoeff() {return coeff;}

    //setters of exponent and coefficient
    public void setExp(int e) {exp = e;}
    public void setCoeff(double c) {coeff = c;}

    //getters of pointers of Polynomial terms
    public Term getPrev() {return prev;}
    public Term getNext() {return next;}

    //setters of pointers of Polynomial terms
    public void setPrev(Term p) {prev=p;}
    public void setNext(Term n) {next=n;}       
}// end Term class

//addterm method
public void addTerm(int e, double c){
    Term last = tail.prev;
    Term temp = new Term(e, c);
    temp.next = tail;
    temp.prev = last;
    tail.prev = temp;
    last.next = temp;
    size++; 
}// end addTerm method

public int size() {return size;}

public boolean isEmpty() {return size==0;}  



public static void main(String[] args) throws IOException {
    // TODO Auto-generated method stub


    FileReader fin = new FileReader("Test.txt");
    Scanner src = new Scanner(fin);
    Scanner lineTokenizer = new Scanner(src.nextLine());
    int lineNum = 0;

    Polynomial p1 = new Polynomial();

        while (src.hasNextLine()) {            

            lineNum++;

            while (lineTokenizer.hasNextInt()){
            p1.addTerm(lineTokenizer.nextInt(), lineTokenizer.nextInt()) ;

        }

        lineTokenizer.close();  
    src.close();

}

}

Answer 1

只需使用BufferedReader，然后将行拆分为不同的数字：

BufferedReader reader = new BufferedReader(new FileReader("Test.txt"));
String line;
while((line = reader.readLine()) != null) {
    String[] nums = line.split(" ");
    //get each num from nums and cast it to integer using Integer.parseInt()
}

Java扫描程序 - 将每行读取为有限数据集

1 个答案: