CODEWITHSUNDEEP
java
user3529205
user3529205

Reputation: 185

Parse input in java from mutiple line

I have got n lines of numbers , all containing equal number of numbers lets say m , how to store them in 2d array 

1 5 7 9  
2 3 4 6  
3 4 5 8

Note that here value of n and m is not given . 

    BufferedReader br = new BufferedReader (new     InputStreamReader(System.in));
    Scanner sc=new Scanner(System.in);
    while(sc.hasNextLine())
    {
    String line=br.readLine();
    String [] str =line.trim().split(" ");
    int n=str.length;
    columns=n;
    for(int i=0;i<n;i++)
    {
        matrix[rows][i]=Integer.parseInt(str[i]);
    }
        rows++;
    }

Runtime error is coming
Runtime error time: 0.14 memory: 321088 signal:-1

Upvotes: 1

Views: 103

Answers (3)

Tim Biegeleisen
Tim Biegeleisen

Reputation: 522406

You can temporarily store everything into an ArrayList, then iterate over it at the end and create your 2D array:

BufferedReader br = new BufferedReader("C:/YourFile.txt");
ArrayList<Integer> list = new ArrayList<Integer>();
int rows=0, cols=0;
String line;
while ((line = br.readLine()) != null) {
    String [] str = line.trim().split(" ");
    int n = str.length;
    cols = n;
    for (int i=0; i < n; ++i) {
        list.add(Integer.parseInt(str[i]));
    }
    ++rows;
}

// now create a 2D array and store everything into it
int[][] array = new array[rows][cols];
for (int i=0; i < rows; ++i) {
    for (int j=0; j < cols; ++j) {
        array[i][j] = list.get(i*cols+j);
    }
}

Upvotes: 2

superbob
superbob

Reputation: 1638

Not sure, but I think using System.in in two objects (Scanner and InputStreamReader) causes issues, as characters may be consumed by the scanner before being read by the reader.

If you leave away the scanner, and just use BufferedReader.ready() in your while condition, it works (nearly the same code) :

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
while(br.ready())
{
    String line=br.readLine();
    String [] str =line.trim().split(" ");
    int n=str.length;
    columns=n;
    for(int i=0;i<n;i++)
    {
        matrix[rows][i]=Integer.parseInt(str[i]);
    }
    rows++;
}

You might prefer Tichodroma's more elegent answer.

Upvotes: 1

user1907906
user1907906

Reputation:

Try this:

    List<List<Integer>> ints = new ArrayList<>();
    String d = "1 5 7 9  \n"
            + "2 3 4 6  \n"
            + "3 4 5 8  ";
    for (String line : d.split("\n")) {
        List<Integer> row = new ArrayList<>();
        for (String cell : line.split(" ")) {
            row.add(Integer.parseInt(cell));
        }
        ints.add(row);
    }
    System.out.println(ints);

Output:

[[1, 5, 7, 9], [2, 3, 4, 6], [3, 4, 5, 8]]

Upvotes: 1

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