Question

If I have the following Java code:

int[][] readAPuzzle()
{
    Scanner input = new Scanner(System.in);

    int[][] grid = new int[9][9];
    for (int i=0; i<9; i++)
      for (int j=0; j<9; j++)
        grid[i][j] = input.nextInt();

    return grid;
}

public static void main(String[] args) {
    // Read a Sudoku puzzle
    int[][] grid = readAPuzzle();
}

How can I convert this to C++? I get hung up on passing the array. Here is my attempt:

#include <iostream>

using namespace std;

const int puzzle_width = 9;
const int puzzle_height = 9;

void readAPuzzle(int (&grid)[puzzle_height][puzzle_width])
{
    for(int i = 0; i < 9; i++)
        for(int j = 0; j < 9; j++)
            grid[i][j] = cin >> grid[i][j];

    return;
}

int main()
{
    int[9][9] grid;
    readAPuzzle(grid);
}

What am I doing wrong in general?

Answer 1

You need to read in the input text into your array grid and pass it on.

grid[i][j] = cin >> grid[i][j];

Doesn’t do what you think it does, it tries to assign an object of type istream to grid[ i ][ j ]

cin >> grid[i][j]; 

however suffices.

Also, note in C++ the dimensions follow the identifier as in:

int grid[9][9];