Need a function to read a file and set it as my sudoku board.

[ninjachachi]

I'm in a very beginners C++ class and we're just getting started on arrays and up to now everything has gone great but arrays baffle me. So in this homework we are given a working c++ program to play sudoku and our goal is to read a file we downloaded "sudokuProblem.txt" which has a board made in the same format and we are to input that filename, read the file, and continue the program from that board. We must properly read files in the format given by
sudokuProblem.txt, with “.” in blank spaces and the “-”, “|” and “+” dividers. We will also have to save the board but if I can figure out the first one I want to struggle on that myself.
Here is the sudokuProblem.txt:

53.|.7.|...
6..|195|...
.98|...|.6.
---+---+---
8..|.6.|..3
4..|8.3|..1
7..|.2.|..6
---+---+---
.6.|...|28.
...|419|..5
...|.8.|.79

and here is the working sudoku program, the functions that we need are already created

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

const int SIZE = 9;
const char BLANK = '.';

int charToInt(char c);
char intToChar(int i);
bool validBoard(const char board[SIZE][SIZE]);
void printBoard(const char board[SIZE][SIZE]);
bool isNumber(char c);
void copyBoard(const char input[SIZE][SIZE], char output[SIZE][SIZE]);
bool isOpenSpot(const char board[SIZE][SIZE]);
bool isOpen(const char board[SIZE][SIZE], int row, int col);


// Make this for part A
void readBoard(char board[SIZE][SIZE], string fileName);

// Make this for part B
void saveBoard(char board[SIZE][SIZE], string fileName);

int main()
{
	string dump;
	char b[SIZE][SIZE];
	for(int i=0; i < SIZE; i++)
	{
		for(int j=0; j < SIZE; j++)
		{
			b[i][j] = '.';
		}
	}
	string message = "";
	while(isOpenSpot(b))
	{
		char row, col;
		cout << "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
		printBoard(b);
		cout << message << endl;
		message = "";
		cout << "Where do you wish to play? (or load/save)  ";
		cin >> row; 
		
		if(tolower(row) == 'l')
		{
			cout << "What file do you wish to load?  ";
			getline(cin, dump);
			getline(cin, dump);
			readBoard(b, dump);
			continue;
		}
		else if(tolower(row) == 's')
		{
			cout << "Where do you wish to save?  ";
			getline(cin,dump);
			getline(cin,dump);
			saveBoard(b, dump);
			continue;
		}
		
		cin >> col;
		getline(cin, dump);
		
		int rrow, rcol;
		if(tolower(row) >= 'a' && tolower(row) <= 'i')
		{
			rrow = tolower(row)-'a';
			rcol = col-'1';
		}
		else
		{
			rcol = tolower(col)-'a';
			rrow = row-'1';			
		}
		if(isOpen(b,rrow,rcol))
		{
			char value;
			cout << "What number should go at "<<row<<col<<"? ";
			cin >> value;
			getline(cin, dump);
			
			char copy[SIZE][SIZE];
			copyBoard(b, copy);
			
			if(value < '1' || value > '9')
			{
				message = "You can only play 1 - 9";
			}
			else
			{
				copy[rrow][rcol] = value;
				
				if(validBoard(copy))
				{
					b[rrow][rcol] = value;
				}
				else
				{
					message = "That is not a valid move";
				}			
			}
		}
		else
		{
			message = "You cannot play there";
		}
	}
}

int charToInt(char c)
{
	return c-'1'+1;
}

char intToChar(int i)
{
	return '1'+(i-1);
}

bool validBoard(const char board[SIZE][SIZE])
{
	// whole board formatting check
	for(int row=0; row < SIZE; row++)
	{
		for(int col=0; col < SIZE; col++)
		{
			if(!(isNumber(board[row][col]) || board[row][col] == BLANK))
			{
				return false;
			}
		}
	} 

	// row check
	for(int row=0; row < SIZE; row++)
	{
		string letters = "";	
		for(int col=0; col < SIZE; col++)
		{
			// if letters doesn't have this character (and its in 1-9)
			if(letters.find(board[row][col])==static_cast<long unsigned>(-1)
				&& isNumber(board[row][col]))
			{
				letters = letters+board[row][col];
			}
			else if(isNumber(board[row][col]))
			{
				return false;
			}
		}
	}
	
	// col check
	for(int col=0; col < SIZE; col++)
	{
		string letters = "";	
		for(int row=0; row < SIZE; row++)
		{
			// if letters doesn't have this character (and its in 1-9)
			if(letters.find(board[row][col])==static_cast<long unsigned>(-1)
				&& isNumber(board[row][col]))
			{
				letters = letters+board[row][col];
			}
			else if(isNumber(board[row][col]))
			{
				return false;
			}
		}
	}
	
	// 3x3 square checks
	for(int b=0; b < SIZE; b++) // boxes
	{
		string letters = "";	
		for(int s=0; s<SIZE; s++) //square in the 3x3
		{
			int row = (b%3)*3 + s%3;
			int col = (b/3)*3 + s/3;
			
			// if letters doesn't have this character (and its in 1-9)
			if(letters.find(board[row][col])==static_cast<long unsigned>(-1)
			 && isNumber(board[row][col]))
			{
				letters = letters+board[row][col];
			}
			else if(isNumber(board[row][col]))
			{
				return false;
			}

		}
	}
	
	return true;
}

void printBoard(const char board[SIZE][SIZE])
{
	cout << "  123 456 789\n";
	for(int row=0; row<SIZE; row++)
	{
		cout << static_cast<char>('a'+row) << ' ';
		for(int col=0; col<SIZE; col++)
		{
			cout << board[row][col];
			if(col%3==2 && col != SIZE-1)
			{
				cout <<"|";
			}
		}
		if(row%3==2 && row != SIZE-1)
		{
			cout << "\n  ---+---+---";
		}
		cout << endl;
	}
}

bool isNumber(char c)
{
	return ('1' <= c && c <= '9');
}

void copyBoard(const char input[SIZE][SIZE], char output[SIZE][SIZE])
{
	for(int row=0; row<SIZE;row++)
	{
		for(int col=0; col<SIZE;col++)
		{
			output[row][col] = input[row][col];
		}
	}
}

bool isOpenSpot(const char board[SIZE][SIZE])
{	
	for(int rrow=0; rrow < SIZE; rrow++)
	{
		for(int rcol=0; rcol < SIZE; rcol++)
		{
			if(!isNumber(board[rrow][rcol]))
			{
				return true;
			}
		}
	}
	
	// didn't find an open spot... =(
	return false;
}

bool isOpen(const char board[SIZE][SIZE], int row, int col)
{
	if(row < 0 || col < 0 || col >= SIZE || row >= SIZE)
	{
		return false;
	}
	
	return board[row][col] < '1' || board[row][col] > '9';
}

// Make this for part A
void readBoard(char board[SIZE][SIZE], string fileName)
{
	// im empty!
}

// Make this for part B
void saveBoard(char board[SIZE][SIZE], string fileName)
{
	// sad code
}

[ninjachachi]

Any help is appreciated! Thanks

[SakurasouBusters]

I'm in a very beginners C++ class

For a very C++ beginner, it is quite a big C++ program you create there.

[ninjachachi]

For a very C++ beginner, it is quite a big C++ program you create there.

The program was created for us, it is our goal to create the readBoard an saveBoard function. And I'm very confused

[ninjachachi]

I can get it to store
53.|.7.|...
6..|195|...
.98|...|.6.
---+---+---
8..|.6.|..3
4..|8.3|..1
7..|.2.|..6
---+---+---
.6.|...|28.
...|419|..5
...|.8.|.79

into the array but it looks more like

53.|.7.|.
..6..|195
|....98|.
..|.6.---
+---+---8
..|.6.|..
34..|8.3|
..17..|.2
.|..6---+
---+---.6
.|...|28.
...|419|.
.5...|.8.
|.79+---8
..|.6.|..
34..|8.3|
..17..|.2
.|..6---+

Is there anyway to skip reading any character unless it is a number or a .?

[gunnerfunner]

If your instructor requires you to produce a 9 * 9 matrix (const int SIZE = 9, as the program reads) then you can't have the dividers as they'd bump up the size of your array. They are therefore removed in the code below. In any case, if you understand this code you should be able to incorporate them if you wish after adjusting the SIZE variable accordingly.

There are comments within the program to aid understanding. Read up further if something is unclear and, if still unsure, do come back here:

#include<iostream>
#include<fstream>
#include<sstream>
#include<string>

using namespace std;

int main(){
char ptr[9][9];//the program outputs the 3 boards simultaneously, constituent boards can be assigned from this array in turn;

   ifstream File;
   File.open("F:\\test.txt");//associate the file which holds the data with the ifstream object, File, that'd read from the .txt file;
   if(File.is_open()){//no further error checks like File not opening, etc, OP to consider this carefully;
    string line;
    char delimiter = '|'; //as explained in opening comments, this character makes SIZE > 9 and hence removed;
    int line_no = 0;

    while(getline(File, line)){// read File into the string, line;

        stringstream stream(line);//instantiate stringstream object, stream, with string, line (OP: read up sstream if unfamiliar);
        string s1, s2, s3;
        if(line == "---+---+---"){
    //skipping lines 4 and 8 which don't have numbers; again, similar to comments re delimiter, can be retained if OP wishes;
                continue;
        }
        getline(stream,s1,delimiter)&&getline(stream,s2,delimiter)&&getline(stream,s3,delimiter);
    // breaks up stream into 3 smaller strings each reading upto, but not including, the delimiter or newline character;
        string s = s1 + s2 + s3;// having got rid of the delimiters, we join the strings back up again!;
        for (int i = 0; i < s.size(); i++){
            ptr[line_no][i] = s[i];// assigning the elements of the joined up string to the rows of the array;
        }
            line_no++;// moving on to the next line;
     }
}
File.close();

   for(int i = 0; i <9; i ++){
    for (int j = 0; j < 9; j++){
        cout<<ptr[i][j]<<"\t";//printing the array to check the program, results shown below;
    }
    cout<<"\n";
   }
}

Output

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