I created a program that is supposed to read two 3D matrices from a binary file, multiply them, and print the result to a binary file. However, while it successfully compiles, when I run it, it gives me a segmentation fault error.

Here is the code I used for the program:

#include <stdio.h>
#include <stdlib.h>

int main() {
        int n;
        int n2;

        int matrix1[n][n][n], matrix2[n][n][n], result_matrix[n][n][n];

        FILE *file1, *file2, *result;

        file1 = fopen("matrix1.bin", "rb");
        file2 = fopen("matrix2.bin", "rb");

        fread(&n, sizeof(int), 1, file1);
        fread(&n2, sizeof(int), 1, file2);

        if (n != n2 || n > 100) {
                printf("Error: Incompatible matrices or n greater than 100.");
                return 1;
        }

        fread(matrix1, sizeof(int), n * n * n, file1);
        fread(matrix2, sizeof(int), n * n * n, file2);

        fclose(file1);
        fclose(file2);

        for (int i = 0; i < n; ++i) {
                for (int j = 0; j < n; ++j) {
                        for (int k = 0; k < n; ++k) {
                                result_matrix[i][j][k] = 0;

                                for (int l = 0; l < n; l++) {
                                        result_matrix[i][j][k] += matrix1[i][j][l] * matrix2[l][j][k];
                                }
                        }
                }
        }

        result = fopen("result.bin", "wb");

        fwrite(&n, sizeof(int), 1, result);
        
        fwrite(result_matrix, sizeof(int), n * n * n, result);

        fclose(result);

        return 0;
}

This is specifically where the segmentation fault is happening:

Program received signal SIGSEGV, Segmentation fault.
0x0000555555555c3a in main () at 31504085_1.c:35
35 result_matrix[i][j][k] += matrix1[i][j][l] * matrix2[l][j][k];

What can you do to help fix this issue?