Confusing Segmentation Fault When Reading From File

Question

So, I'm trying to read a file of integers into 2 separate matrices. The first matrix is read in perfectly fine. Then the second one tries to read in from the file, gets to the last line and gets to a segfault. I have looked over the code about a bazillion times and can't figure out why I'm getting this segfault. Any help would be helpful!

Relevant code is pasted below:

int** allocation_matrix;
int** request_matrix;

allocation_matrix = (int **) malloc(num_processes * sizeof(int));
request_matrix    = (int **) malloc(num_processes * sizeof(int));

for (i = 0; i < num_processes; i++)
{
    allocation_matrix[i] = (int *) malloc(num_resources * sizeof(int));
    request_matrix[i]    = (int *) malloc(num_resources * sizeof(int));
}

for (i = 0; i < num_processes; i++)
{
    for (j = 0; j < num_resources; j++)
    {
        fscanf(fp, "%d", &allocation_matrix[i][j]);
    }
}

for (i = 0; i < num_processes; i++)
{
    for (j = 0; j < num_resources; j++)
    {
        fscanf(fp, "%d", &request_matrix[i][j]);
        printf("%d ", request_matrix[i][j]);
    }
    printf("\n");
}

Answer 1

num_processes * sizeof(int) is the wrong size as the wrong type was used.

Instead of trying to use the right type with the pointer, determine the size based on the de-referenced pointer. Easier to code right, review and maintain.

// allocation_matrix = (int **) malloc(num_processes * sizeof(int));
allocation_matrix = malloc(sizoef *allocation_matrix * num_processes);