How do I make a maze tile 3x3 - c++

Question

Like the question says, I have a 10X11 array and I need each tile to be a 3x3 instead of 1x1 and Im not sure how to do that. I also am having trouble pulling the correct x value for my finish point. Any help would be much appreciated. here is my code so far:
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <vector>
int main()
{
//establishing constant variables;
const char Walls = '#';
const char Mazes = '-';
const int row = 10;
const int col = 11;
//defining strings to pull from text file
std::string arraysize_sx;
std::string arraysize_sy;
std::string start_sx;
std::string start_sy;
std::string finish_sx;
std::string finish_sy;
std::string walls_s;
std::ifstream openfile ("input.txt");
std::ofstream outputfile ("output.txt",std::ios::app);
//gets points from text file, using , and . as delimiters
std::getline(openfile, arraysize_sx , ',');
std::getline(openfile, arraysize_sy, '.');
std::getline(openfile, start_sx, ',');
std::getline(openfile, start_sy, '.');
std::getline(openfile, finish_sx , ',');
std::getline(openfile, finish_sy , '.');
std::getline(openfile,walls_s, '.');
int startx,starty;
int finishx,finishy;
//convert string to int
std::stringstream rowconv(arraysize_sx);
std::stringstream colconv(arraysize_sy);
std::stringstream startsx(start_sx);
std::stringstream startsy(start_sy);
std::stringstream finishsx(finish_sx);
std::stringstream finishsy(finish_sy);
// rowconv >> row;
// colconv >> col;
startsx >> startx;
startsy >> starty;
finishsx >> finishx;
finishsy >> finishy;
//defining the shape of the maze
char maze [col][row] = {
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
{'-','-','-','-','-','-','-','-','-','-'},
};
maze[startx][starty] = 's';
maze[finishx+3][finishy] = 'f';
outputfile << *maze;
openfile.close();
}
Here is my .txt input for refrence, each different point is marked by a period. i.e dimentions. start. finish. walls:
10, 11.
(0, 0).
(3, 10).
(0, 6), (0, 7), (0, 9),
(1, 1), (1, 2), (1, 4), (1, 7),
(2, 1), (2, 7), (2, 8), (2, 10),
(3, 1), (3, 2), (3, 3), (3, 4), (3, 7),
(4, 0), (4, 6), (4, 9), (4, 10),
(5, 2), (5, 3), (5, 4), (5, 5), (5, 7),
(6, 1), (6, 8), (6, 9),
(7, 1), (7, 2), (7, 3), (7, 6),
(8, 1), (8, 5), (8, 6), (8, 8), (8, 10),
(9, 3), (9, 7).
Update:
I updated my code so that instead of creating the array like I did above. I used for loops to create the start and finish. Im still working on adding the walls in and creating 3X3 squares for each point. I'm trying to find out if its possible to place a 3X3 array within one point on another array.
Updated code:
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <vector>
int main()
{
//establishing constant variables;
const int row = 10;
const int col = 11;
double p1x,p1y;
//defining strings to pull from text file
std::string arraysize_sx;
std::string arraysize_sy;
std::string start_sx;
std::string start_sy;
std::string finish_sx;
std::string finish_sy;
// std::string walls_sx;
// std::string walls_sy;
std::string walls_sf;
std::ifstream openfile ("input.txt");
std::ofstream outputfile ("output.txt",std::ios::app);
// int wx,wy;
int startx,starty;
int finishx,finishy;
//gets points from text file, using , and . as delimiters
std::getline(openfile, arraysize_sx , ',');
std::getline(openfile, arraysize_sy, '.');
std::getline(openfile, start_sx, ',');
std::getline(openfile, start_sy, '.');
std::getline(openfile, finish_sx , ',');
std::getline(openfile, finish_sy , '.');
// std::getline(openfile,walls_sx, ',');
// std::getline(openfile,walls_sy, ',');
std::getline(openfile,walls_sf, '.');
//convert string to int
std::stringstream rowconv(arraysize_sx);
std::stringstream colconv(arraysize_sy);
std::stringstream startsx(start_sx);
std::stringstream startsy(start_sy);
std::stringstream finishsx(finish_sx);
std::stringstream finishsy(finish_sy);
// std::stringstream wallx(walls_sx);
// std::stringstream wally(walls_sy);
startsx >> startx;
startsy >> starty;
finishsx >> finishx;
finishsy >> finishy;
// wallx >> wx;
// wally >> wy;
//defining the shape of the maze
char maze [col][row];
char s [3][3] = {
{'-','-','-'},
{'-','S','-'},
{'-','-','-'}
};
//defining the start point and endpoint using the points pulled from the text file
for (int x = 0; x < col; x++){
for (int y = 0; y < row; y++){
if (x == startx && y == starty){
maze[x][y] = 'S';
}
else if (y == finishx+3 && x == finishy){
maze[x][y] = 'F';
}
else{
maze [x][y] = '-';
}
}
}
std::cout << walls_sf << std::endl;