Breadth first search - count connected elements - peer code using C++

BFS_CountconnectedElements_peerCode.cpp

#include <iostream>
#include <vector>
#include <queue>

using namespace std;

struct vec2i {
  int x, y;
};

void bfs(vector<vector<int>>& binaryMatrix, int rows, int cols, vec2i pos) {
  deque<vec2i> q;
  q.push_back(pos);
  while (!q.empty()) {
    vec2i cur = q.front();
    q.pop_front();
    
    if (cur.x >= 0 && cur.x < rows && cur.y >= 0 && cur.y < cols) {
      int& value = binaryMatrix[cur.x][cur.y];
      if (value == 1) {
        value = 0;
        
        // Add neighbours:
        q.push_back(vec2i{cur.x - 1, cur.y}); // Left
        q.push_back(vec2i{cur.x + 1, cur.y}); // Right
        q.push_back(vec2i{cur.x, cur.y - 1}); // Top
        q.push_back(vec2i{cur.x, cur.y + 1}); // Top
      }
    }
  }
}

int getNumberOfIslands( const vector<vector<int>>& binaryMatrix ) 
{
  auto binaryMatrixMutable = binaryMatrix;
  int num_islands = 0;
  int rows = binaryMatrix.size();
  int cols = (rows ? binaryMatrixMutable[0].size() : 0);
  for (int row = 0; row < rows; ++row) {
    for (int col = 0; col < cols; ++col) {
      int value = binaryMatrixMutable[row][col];
      if (value == 1) {
        bfs(binaryMatrixMutable, rows, cols, vec2i{row, col});
        ++num_islands;
      }
    }
  }
  return num_islands;
}

int main() {
  return 0;
}

Ask the peer about C++ using struct, instead of using array
void f(int arr[256]) {
cerr << "Size of the parameter: " << sizeof(arr) << "\n";
} // empty array will return size of 8.

int main() {
f(nullptr);
return 0;
}