ArrayList get（）方法不返回第一个索引值

Question

I created an arrayList to store String values.When i am going to fetch values from my arrayList it doesn't return me the first value of it;s 0th index.

ArrayList<String> arrayList = new ArrayList<String>();
Scanner scan= new Scanner(System.in);
int noInput=scan.nextInt();

for(int i=0; i < noInput/2; i++)
   arrayList.add(scan.nextLine());       

for(int i=0;i<arrayList.size();i++)
   System.out.println("ArrayList:"+arrayList.get(i) + " "  + i );

Answer 1

使用scan.next()而不是scan.nextLine() 。

Answer 2

Because Scanner#nextInt reads only the int value, then nextLine in the first iteration will consume the remaining \\n (the enter you hit after you entered the integer value).

To fix this, add nextLine after nextInt or use next instead of nextInt .

Answer 3

It is probably because your list is never filled. I think the first loop isn't gone into, so nothing is added to the array.
for(int i=0; i < noInput/2; i++) arrayList.add(scan.nextLine());

Try debugging it or printing the size of the arraylist