二维数组中带有空格的字符串输入

Question

I want to take string inputs in java which is separated by spaces in a 2D array and display all the items in a separate line.

eg:
input:

item1 3 5
item2 7 4

output:

item1
3
5
item2
7
4

Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int b = sc.nextInt();
String array_of_items[][] = new String[a][b];
for(int i=0;i<a;i++)
{ 
  String str = sc.nextLine(); 
  String[] lineVector = str.split(" ");
  for(int j=0;j<b;j++)
  {
    array_of_items[i][j] = lineVector[j];
  }
}

for(int i=0;i<a;i++)
{
  for(int j=0;j<b;j++)
  {
    System.out.println(array_of_items[i][j]);
  }
}

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1

Answer 1

The first String str = sc.nextLine(); reads the new line from int b = sc.nextInt(); so your lineVector is empty => ArrayIndexOutOfBoundsException when you try to access lineVector[j] . The fix is to consume that line by adding a sc.nextLine(); after int b = sc.nextInt(); .

Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int b = sc.nextInt();
sc.nextLine();
String array_of_items[][] = new String[a][b];
for (int i = 0; i < a; i++) {
    String str = sc.nextLine();
    String[] lineVector = str.split(" ");
    for (int j = 0; j < b; j++) {
        array_of_items[i][j] = lineVector[j];
    }
}
for (int i = 0; i < a; i++) {
    for (int j = 0; j < b; j++) {
        System.out.println(array_of_items[i][j]);
    }
}

Input

2
3
1 2 3
4 5 6

Output

1
2
3
4
5
6