Seg fault when assigning a value to a 2D vector in C++

Question

Ive been trying to change the values in this vector but keep getting stuck with a segmentation fault. I initialized the vector so i can get a rectangle of values in the vector, using zeros as fillers.

#include <bits/stdc++.h>
#include <vector>
using namespace std;

// vector initializer
void iniciaMat(vector<vector<int>> matAdj, int n, int m) {
  for (int i = 0; i < n; i++) {
    vector<int> linea;
    for (int j = 0; j < m; j++) {
      linea.push_back(0);
    }
    matAdj.push_back(linea);
  }
}

void leeArcos(vector<vector<int>> matAdj, int m) {
  int c, num1, num2;
  char val1, val2;
  for (int i = 0; i < m; i++) {
    cin >> val1 >> val2 >> c;
    num1 = val1 - 'A';
    num2 = val2 - 'A';

    matAdj[num1][num2] = c;
    matAdj[num2][num1] = c;
  }
}

void printVec(vector<vector<int>> matAdj, int n, int m) {
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cout << matAdj[i][j] << " " << endl;
    }
    cout << endl;
  }
}
int main() {
  // n is the number of nodes i.e. V
  int n, m;
  cin >> n >> m;
  vector<vector<int>> matAdj;
  iniciaMat(matAdj, n, m);
  leeArcos(matAdj, m);
  printVec(matAdj, n, m);
  return 0;
}