-2
- 使用ArrayList类的toString方法打印ArrayList。
- 询问用户名称以从列表中删除。如果在列表中找不到该名称,请打印一条消息,指出该名称不在列表中。如果找到了,请删除名称,然后打印当前列表。
我似乎无法得到toString方法的工作,也没有“如果找到列表,删除名称,并打印当前列表”。Java ArrayList toString&用户从列表中删除名称后的更新列表
public static void main(String[] args) throws IOException
{
ArrayList<String> list = new ArrayList<String>();
// Open the file
File file = new File("input.txt");
Scanner inputFile = new Scanner(file);
// Read until the end of the file
while(inputFile.hasNext()){
//String str = inputFile.nextLine();
list.add(inputFile.next());
System.out.println(list.toString() + " " + list.size());
}
inputFile.close();
// Add a name to the end of the list
list.add("Michael");
System.out.println("\nMichael is added to the end of the list: \n" + list.toString());
// Add a name to the list in position 2
list.add(2, "Lucy");
System.out.println("\nLucy is added to the list as the third name: \n" + list.toString());
// Find the indexOf Michael
System.out.println("\nindexOf Michael is: " + list.indexOf("Michael"));
// Replace Michael with Mike
list.set(11, "Mike");
System.out.println("\nReplace Michael with Mike: \n" + list.toString());
// Ask user for a name to delete from the list
Scanner input = new Scanner(System.in);
System.out.print("What name would you like to delete from the list? ");
String deleteName = input.nextLine();
// If name not found then display message
boolean found = false;
if(found == false)
System.out.println("The name is not on the list");
// If name found then delete name and show current ArrayList
for(String a: list){
if(a.compareTo(deleteName) == 0){
list.remove(a);
System.out.println(a + " was deleted from the list. Here is the new list: \n" +
list.toString());
}
}
// String str = (String)nameList.get(0);
}
// Use toString method of the ArrayList Class.
public String toString()
{
return list.toString();
}
定义“我不能”。你期望代码做什么,它做什么呢? – 2014-10-03 07:04:01
“找不到符号 - 变量列表”toString(),我不知道如何去通过toString()返回列表。 – Bob 2014-10-03 07:13:27
错误的行号是什么?该行有没有可用的列表?线路变量在哪里定义?你真的认为方法中定义的变量可用于任何其他方法吗?按照问题,主要方法的代码已经使用了ArrayList的toString()方法。我不确定你为什么要在你的类中定义一个toString()方法。 – 2014-10-03 07:14:41