Fib matrice

/* fib pe parelelele la diagonala secundara. */
#include <stdio.h>
#include <stdlib.h>
#define SUCCESS (0)
#define INVALID_INPUT (1)
#define NEWLINE printf("\n")

long sum(long a, long b);
int numberlen(long n);
int strlen_(char *s);
long strtol_(char *number);
void validate(long n, char *number);
void scanf_number(long *n);

void *ec_realloc(void *ptr, unsigned int size)
{
    void *new_ptr;

    new_ptr = realloc(ptr, size);

    if (!new_ptr) {
        printf("[Error] ec_realloc(): realloc() returned NULL.");
        exit(-1);
    }

    return new_ptr;
}

void *ec_malloc(unsigned int size)
{
    return ec_realloc(NULL, size);
}


int main()
{
    int n;
    scanf_number((long *)&n);

    long **mat;

    mat = (long **) ec_malloc(n * sizeof(long *));

    for (int i = 0; i < n; i++) {
        mat[i] = (long *)ec_malloc(n * sizeof(long));
    }

    long fib, pre, antepre;
    fib = 0;
    antepre = 0;
    pre = 1;

    for (
        int col = 0;
        col < n - 1;
        col++
        )
    {
        for (
            int ln = 0;
            ln < col+1;
            ln++
            )
        {
            mat[ln][col - ln] = fib;

            fib     = antepre + pre;
            antepre = pre;
            pre     = fib;
        }
    }
    for (
        int ln = 1;
        ln < n;
        ln++
        )
    {
        for (
            int col = n - 1;
            col > ln-1;
            col--
            )
        {
            mat[ln+(n-1)-col][col] = fib;
            fib     = antepre + pre;
            antepre = pre;
            pre     = fib;
        }
    }
    NEWLINE;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            printf("%10ld", mat[i][j]);
        }
        NEWLINE;
    }
    return 0;
}

/* strtol wrapper
 * Returns the number string converted to n.
 * If conversion "failed", it returns 1.
 */
long strtol_(char *number)
{
    char *err = "";
    /* convert */
    long n = strtol(number, &err, 10);
    /* check */
    if (*err) {
        return INVALID_INPUT;
    }
    return n;
}
int strlen_(char *s)
{
    int nr = 0;
    for (; *s; s++, nr++) { ; }
    return nr;
}
/* Validate conversions with strtol_.
 * If conversion is invalid terminate execution. !!
 * */
void validate(long n, char *number)
{
    if (
        1 == n &&
        numberlen(n) != strlen_(number)
        )
    {
        printf("Please enter a valid integer.\n");
        exit(INVALID_INPUT);
    }
}
/* Validated read of one long number. */
void scanf_number(long *n)
{
    char number[1000];
    scanf("%s", number);
    *n = strtol_(number);
    validate(*n, number);
}

int numberlen(long n)
{
    int nr = 0;
    for (; n; n /= 10, nr++) { ; }
    return nr;
}