Input/Output file using classes (Sudoku Solver)

First, I am a beginner coder and I have tried to tackle and solve parts of my problem for hours and can not figure it out.

I have done all the task except for two tasks: 1.) I can not figure out how to use input and outfile mechanism of ifstream and ofstream to get my .txt file to set my values for my sudoku board. 2.) I cannot seem to figure out how to print out a sudoku board for each "possible values" for each xyposition in the cells.

I am trying to implement a text file that reads:

  puzzle.setBoardValue(0,0,1);
  puzzle.setBoardValue(1,1,3);
  puzzle.setBoardValue(2,2,9);

  puzzle.setBoardValue(3,2,6);
  puzzle.setBoardValue(4,1,2);
  puzzle.setBoardValue(5,0,7);

  puzzle.setBoardValue(6,2,5);
  puzzle.setBoardValue(7,0,9);
  puzzle.setBoardValue(8,1,8);

  puzzle.setBoardValue(0,5,6);
  puzzle.setBoardValue(1,4,1);
  puzzle.setBoardValue(2,3,5);

  puzzle.setBoardValue(3,3,3);
  puzzle.setBoardValue(4,4,8);
  puzzle.setBoardValue(5,5,4);

  puzzle.setBoardValue(6,3,9);
  puzzle.setBoardValue(8,4,2);

  puzzle.setBoardValue(0,6,3);
  puzzle.setBoardValue(1,7,4);
  puzzle.setBoardValue(2,8,7);

  puzzle.setBoardValue(6,8,3);
  puzzle.setBoardValue(7,6,1);
  puzzle.setBoardValue(8,7,7); `

and basically use that to and automatically direction my program to the function void setBoardValue(); All I have figured out was in my int main(); where I put

cout << "Enter filename:" << endl;
cin >> filename;
in.open(filename);
while(getline(in,line)){
...

Secondly, I just can not figure out how to print all the possible values for each number cells.

Here is my entire program code:

#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

class SudokuPuzzle{

private:
  unsigned short board[9][9];
  char BlankChar;
  bool debug;
  void printTracerTryingValue(int xpos, int ypos);
  bool solve(int xpos, int ypos);
  bool verifyValue(int xpos, int ypos);

public:
  SudokuPuzzle();
  void print();
  void setBoardValue(int xpos, int ypos, int value);
  int getBoardValue(int xpos, int ypos);
  bool solve();
};

SudokuPuzzle::SudokuPuzzle(){
  debug = false;
  for (int i = 0; i < 9; ++i){
    for (int j = 0; j < 9; ++j){
      board[j][i] = 0;
    }
  }
}

void SudokuPuzzle::print(){
  for (int y = 0; y < 9; y++){
    if (y % 3 == 0){
      cout << "-------------------------------" << endl;
    }
    for (int x = 0; x < 9; x++){
      if (x % 3 == 0){
        cout << "|";
      }
      if (board[x][y] != 0){
        cout << " " << board[x][y] << " ";
      }
      else{
        cout << " . ";
      }
    }
    cout << "|" << endl;
  }
  cout << "-------------------------------" << endl;
}

void SudokuPuzzle::setBoardValue(int xpos, int ypos, int value){
   board[xpos][ypos] = value;
}

void SudokuPuzzle::setBoardValue(int xpos, int ypos, int value){
  board[xpos][ypos] = value;
}

bool SudokuPuzzle::solve(){
  return solve(0,0);
}

void SudokuPuzzle::setBoardValue(int xpos, int ypos, int value){
  board[xpos][ypos] = value;
}

bool SudokuPuzzle::solve(){
  return solve(0,0);
}

int SudokuPuzzle::getBoardValue(int xpos, int ypos){
  return board[xpos][ypos];
}

bool SudokuPuzzle::solve(int xpos, int ypos){
  if (board[xpos][ypos] != 0){
    if (verifyValue(xpos, ypos)){
      if (xpos == 8 && ypos == 8){
        return true;
      }
      int next_x = xpos+1;
      int next_y = ypos;
      if (next_x >= 9){
        next_x = 0;
        next_y++;
      }
      return solve(next_x, next_y);
    }
    else{
      return false;
    }
  }
  for(int value = 1; value < 10; value++){
    setBoardValue(xpos, ypos, value);
    if (verifyValue(xpos, ypos)){
      if (xpos == 8 && ypos == 8){
        return true;
      }
      int next_x = xpos+1;
      int next_y = ypos;

      if (next_x >= 9){
        next_x = 0;
        next_y++;
      }
      if (solve(next_x, next_y)){
        return true;
      }
    }
  }

  board[xpos][ypos] = 0;
  return false;
}
bool SudokuPuzzle::verifyValue(int xpos, int ypos){
  printTracerTryingValue(xpos, ypos);
  int value = board[xpos][ypos];
  for (int x_verify = 0; x_verify < 9; x_verify++){
    if (x_verify == xpos){
      continue;
    }
    int verifyValue = board[x_verify][ypos];
    if (verifyValue == value){
      return false;
    }
  }
  for (int y_verify = 0; y_verify < 9; y_verify++){
    if (y_verify == ypos){
      continue;
    }
    int verifyValue = board[xpos][y_verify];
    if (verifyValue == value){
      return false;
    }
  }

  int box_x = xpos / 3;
  int box_y = ypos / 3;

  for (int y_verify = box_y * 3; y_verify < box_y * 3 + 3; y_verify++){
    for (int x_verify = box_x * 3; x_verify < box_x * 3 + 3; x_verify++){
      if (x_verify == xpos && y_verify == ypos){
        continue;
      }

      int verifyValue = board[x_verify][y_verify];
      if (verifyValue == value){
        return false;
      }
    }
  }
  return true;
}

void SudokuPuzzle::printTracerTryingValue(int xpos, int ypos){
  if(debug){
    for (int i = 0; i < xpos+ypos; i++){
      cout << " ";
    }
    cout << "Trying value " << board[xpos][ypos] << " at board[" << xpos << "][" \
<< ypos <<"]" << endl;
  }
}

int main(int argc, char *const argv[]){
  SudokuPuzzle puzzle;
  string filename;
  string line;
  ifstream in;
  ofstream out;

  cout << "Enter filename:" << endl;
  cin >> filename;
  in.open(filename);
  while(getline(in, line)){
    puzzle.line.print()
  }
  cout << endl;

  if(puzzle.solve()){
    cout << "Solution:" << endl;
    puzzle.print();
  }
  else{
    cout << "Puzzle is not solvable.";
  }
  cout << endl;
  return 0;
}