Find path in grid if possible using Recursion - c++

Question

Given a grid of size R X C and startPosition and endPosition of a person in a grid composed of zero and one. Now I want to find path from start position to end position, and also trace the marked path on grid by labelling them 2. If path is not possible, I need to tell that path is not possible. So I had written this logic :
vector<vector<int>> solution;
void printSolution(vector<vector<int>> grid)
{
for (int i=0;i<grid.size();i++)
{
for (int j=0;j<grid[i].size();j++)
cout<<grid[i][j]<<" ";
cout<<endl;
}
}
bool isSafe(vector<vector<int>> grid, pair<int,int> position)
{
if(position.first >= 0 && position.first < grid.size() &&
position.second >= 0 && position.second < grid[0].size() &&
grid[position.first][position.second] == 0)
return true;
return false;
}
bool checkPath(vector<vector<int>> grid,pair<int,int> currentPosition,pair<int,int> endPosition){
if(currentPosition == endPosition)
{
solution[currentPosition.first][currentPosition.second] = 2;
return true;
}
if(isSafe(grid,currentPosition) == true)
{
solution[currentPosition.first][currentPosition.second] = 2;
if (checkPath(grid, make_pair(currentPosition.first+1,currentPosition.second),endPosition) == true)
return true;
if (checkPath(grid, make_pair(currentPosition.first-1,currentPosition.second),endPosition) == true)
return true;
if (checkPath(grid, make_pair(currentPosition.first,currentPosition.second+1),endPosition) == true)
return true;
if (checkPath(grid, make_pair(currentPosition.first,currentPosition.second-1),endPosition) == true)
return true;
solution[currentPosition.first][currentPosition.second] = 0;
return false;
}
return false;
}
bool solver(vector<vector<int>> grid,pair<int,int> startPosition,pair<int,int> endPosition,int R,int C){
solution.resize(R,vector<int>(C));
bool isPath = checkPath(grid,startPosition,endPosition);
printSolution(solution);
if(isPath==false){
cout<<"No Path Found"<<endl;
return false;
}
else{
cout<<"Path Found"<<endl;
return true;
}
}
This code is giving segmentation error. Please help to find it. I am stuck for almost a whole day to find where it is present.
So help me correct the logic of code. Assume I have following fields :
int R,C;
int grid[R][C];
pair<int,int> startPosition;
pair<int,int> endPosition;
This recursion is running infinite. i Checked for a simple case with startPosition as (1,0) and endPosition as (2,2) , R=3 and C=3 and grid as :
1 1 1
0 0 1
1 0 0
First, I tried with BFS, then start to make recursive solution.

Answer 1

When implementing a BFS path finding algorithm, it helps to have a shadow array that keeps track of the distance from the origin for all visited nodes.
int distance[R][C];
Initially, set all of the distances to -1 to indicate that the location has not been visited. Then set the distance at the origin to 0, and push the origin onto the stack.
While the stack is not empty, pop an item from the stack. For each adjacent location (that hasn't been visited) set the distance for that location, and push that location.
When you reach the end position, you can find the path by working backwards. Knowing the distance at the end position, the previous point on the path is an adjacent position that has been visited, and has a lower distance.