Count the determinant. Subtract from each element of the main diagonal X - c++

Question

My program counts the determinant of a matrix.
square matrix size = 3
source
the matrix
1 2 3
4 5 6 -> и вычесть из каждого элемента главной диагонали X
7 8 9
1-x 2 3
4 5-x 6 ->решить определитель
7 8 9-x
#include<iostream>
#include<math.h>
using namespace std;
int determinant(int matrix[10][10], int n) {
int det = 0;
int submatrix[10][10];
if (n == 2)
return ((matrix[0][0] * matrix[1][1]) - (matrix[1][0] * matrix[0][1]));
else {
for (int x = 0; x < n; x++) {
int subi = 0;
for (int i = 1; i < n; i++) {
int subj = 0;
for (int j = 0; j < n; j++) {
if (j == x)
continue;
submatrix[subi][subj] = matrix[i][j];
subj++;
}
subi++;
}
det = det + (pow(-1, x) * matrix[0][x] * determinant(submatrix, n - 1));
}
}
return det;
}
int main() {
int n, i, j,x;
int matrix[10][10];
cout << "Enter the size of the matrix:\n";
cin >> n;
cout << "Enter the elements of the matrix:\n";
for (i = 0; i < n; i++)
for (j = 0; j < n; j++)
cin >> matrix[i][j];
cout << "The entered matrix is:" << endl;
for (i = 0; i < n; i++) {
for (j = 0; j < n; j++)
cout << matrix[i][j] << " ";
cout << endl;
}
cout << "Determinant of the matrix is " << determinant(matrix, n);
return 0;
}