how can i create a grid with java using toStrings-CodePudding

Hi Im new to java and I would like to create a grid using java

I want my output to look like this

1 2 
3 4

How can I do it with just the toStrings method? I am thinking of using a constructor where if I put (int 2) then it will give me this grid, and if it is (int 3) then it will look like:

1 2 3
4 5 6

CodePudding user response：

You need to use nested for loops. Your method need to take 3 parameters for the row count and column count and also a start number (if say you want to start from 10 instead of 1)

private static String generateGrid(int rows, int cols, int start){
        StringBuilder gridBuilder = new StringBuilder();
        int nextNumber = start;
        for(int row = 0 ; row < rows; row  ){
           for(int col = 0 ; col < cols; col  ){
                gridBuilder.append(nextNumber);
                gridBuilder.append(" ");
                nextNumber  ;
           }
           gridBuilder.append("\n");
        }
        return gridBuilder.toString();
    }

The method returns a String. You are free to print the result or use it for other purposes

CodePudding user response：

Since an answer was already provided, I will post mine:

public static void main(String[] args) throws Exception {
    int[][] matrix = {{1,2,3}, {4,5,6}, {7,8,9}};
    printGrid(matrix);
}

public static void printGrid(int[][] matrix) {
    for (int[] row : matrix) {
        for (int value : row) {
            System.out.print(value   " ");
        }
        System.out.println();
    }
}

If you are really concerned about the extra space next to the value, add a string buffer and trim it out before displaying:

public static void printGrid(int[][] matrix) {
    for (int[] row : matrix) {
        StringBuilder buffer = new StringBuilder();
        for (int value : row) {
            buffer.append(value   " ");
        }
        System.out.println(buffer.toString().trim());
    }
}

By the way, the output of this program is

1 2 3
4 5 6
7 8 9