员工计划。JAVA基础知识

Question

我正在写一个简单的启动java程序。我面临的问题是公司名称没有正确添加。

public class Company {
    public static BufferedReader br;
    public static BufferedReader br1;
    public static String numberOfCompanies;

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        CompanyDetails qw = new CompanyDetails();

        try{
            //Scanner in = new Scanner(System.in);
            br = new BufferedReader(new InputStreamReader(System.in));
            br1 = new BufferedReader(new InputStreamReader(System.in));
            System.out.println("Enter number of companies: ");
            numberOfCompanies = br.readLine();
            int G = Integer.parseInt(numberOfCompanies);

            for (int i = 1; i <= G; i++) {
                qw = new CompanyDetails();
                System.out.println("Enter name of the company: ");
                String company = br1.readLine();
                qw.company(company, i);
            }
            for (int i = 0; i <= G; i++) {
            qw.companySummary(G);
            }
        } catch (IOException io) {
            io.printStackTrace();
        }

    }   
}

class CompanyDetails {
    String company, name;
    public String input;
    public static BufferedReader br;
    public double iE;
    public static String numberOfCompanies;
    String nameOfCompany;
    String[] nameofCompany1 = new String[100];
    int ir,i,employee;
    ArrayList<String> bulk = new ArrayList<String>();

    public String[] company(String input, int i) {
        // TODO Auto-generated method stub
        //ArrayList bulk = new ArrayList();
        //for(int ith = i; ith<= 2; i++){
        nameOfCompany = i+input;
        bulk.add(nameOfCompany);
        bulk.add(nameOfCompany);
    //  }
        return nameofCompany1;
    }

    public void employee(double d) {
        // TODO Auto-generated method stub
        ir = (int)d;
    }

    public void companySummary(int G) {

        System.out.println("Number of companies: " + G);
        System.out.println("Name of company: " +bulk +" ");
        System.out.println("Number of employees: "+ir); 
    }   
}

我得到的输出是

​

​

为什么我在数组列表的第一位没有得到234 ?？

Answer 1

您将在循环的每次迭代中创建一个新的CompanyDetails对象，这是通过丢失先前的对象来实现的：

for (int i = 1; i <= G; i++) {
   qw = new CompanyDetails();

您已经在main方法的开头创建了一个CompanyDetails对象：

CompanyDetails qw = new CompanyDetails();

因此，您不必在for循环中再次执行此操作。

Answer 2

public String[] company(String input, int i) {

nameOfCompany = i+input;
bulk.add(nameOfCompany);
bulk.add(nameOfCompany); .// Why are you adding nameOfCompany twice .
return nameofCompany1;    //Why are you returning nameofCompany1 which is null here 

}

 qw = new CompanyDetails();  //this line should be out of the loop.

在Naming Convention上工作。请提供更多关于您想要做什么以及您期望的输出的详细信息。

Answer 3

看一下代码片段：qw = new CompanyDetails();是按循环实例化的。

它应该是：

 qw = new CompanyDetails();
 for (int i = 1; i <= G; i++) {
  ...
 }

正如@CodeBuzz指出的:删除company()方法中的bulk.add(nameOfCompany);，也不要迭代qw.companySummary(G);方法。