Backtracking: Find all the paths from top left cell to the mid cell of the matrix

Given a square maze containing positive numbers, find all paths from top left cell to the middle cell. We can move exactly n steps from a cell in 4 directions i.e. North, East, West and South where n is value of the cell.

Here is my code, please help to find the bug. Not getting the output. I used the backtracking to get the output. I think its going for an infinite loop. Can't find the bug.

#include <bits/stdc++.
#define r 9
#define c 9
using namespace std;

bool is_valid(pair<int , int> pt , set<pair<int , int> > visited) {
    return (pt.first >= 0 && pt.second >= 0 && pt.first < r && pt.second < c && visited.find(pt) == visited.end());
}

void print(vector<pair<int , int> > path) {
    for (int i = 0 ; i < path.size() ; ++i)
        cout<<"("<<path[i].first<<","<<path[i].second<<")->";
    cout<<"END"<<endl;

}

void bar(int arr[][c] , vector<pair<int , int> > path , set<pair<int , int> > visited , int x , int y) {
    if (x == r/2 && y == c/2) {
        print(path);
        return;
    }
    pair<int , int> pt;
    pt = make_pair(x + arr[x][y] , y);
    if (is_valid(pt , visited)) {
        visited.insert(pt);
        path.push_back(pt);
        bar(arr , path , visited , pt.first , pt.second);
        visited.erase(pt);
        path.pop_back();
    }
    pt = make_pair(x - arr[x][y] , y);
    if (is_valid(pt , visited)) {
        visited.insert(pt);
        path.push_back(pt);
        bar(arr , path , visited , pt.first , pt.second);
        visited.erase(pt);
        path.pop_back();
    }
    pt = make_pair(x , y + arr[x][y]);
    if (is_valid(pt , visited)) {
        visited.insert(pt);
        path.push_back(pt);
        bar(arr , path , visited , pt.first , pt.second);
        visited.erase(pt);
        path.pop_back();
    }
    pt = make_pair(x , y - arr[x][y]);
    if (is_valid(pt , visited)) {
        visited.insert(pt);
        path.push_back(pt);
        bar(arr , path , visited , pt.first , pt.second);
        visited.erase(pt);
        path.pop_back();
    }
}

void foo(int arr[][c]) {
    set<pair<int , int> > visited;
    vector<pair<int , int> > path;
    int x = 0;
    int y = 0;
    visited.insert(make_pair(0 , 0));
    path.push_back(make_pair(0 , 0));
    bar(arr , path , visited , x , y);
}

int main() {
    int maze[r][c] =
    {
        { 3, 5, 4, 4, 7, 3, 4, 6, 3 },
        { 6, 7, 5, 6, 6, 2, 6, 6, 2 },
        { 3, 3, 4, 3, 2, 5, 4, 7, 2 },
        { 6, 5, 5, 1, 2, 3, 6, 5, 6 },
        { 3, 3, 4, 3, 0, 1, 4, 3, 4 },
        { 3, 5, 4, 3, 2, 2, 3, 3, 5 },
        { 3, 5, 1, 3, 7, 5, 3, 6, 4 },
        { 3, 5, 4, 3, 2, 6, 4, 4, 3 },
        { 6, 2, 4, 3, 4, 5, 4, 5, 1 }
    };
    foo(maze);
}