Citire/Afisare matrice cu un pointer + pus diag in pointer

#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#pragma warning (disable:4996)


void citireafisare(int n, int m, int*p);
void diagvector(int *p, int dim);

int* alocare(int dim) {

    int *p;

    if ((p = (int*)malloc(sizeof(int) * dim)) == NULL) {
        printf("Nu e saptiu suficient");
        exit(0);
    }

    return p;
}

void citireafisare(int n, int m, int*p) {

    int *p_init = p;
    int dim = n * m;

    for (int i = 0; i < n*m; i++) {
        printf("Elementul p[%d][%d] al lui p =", i / m, i%m);
        scanf("%d", p);
        p++;
    }

    p = p_init;

    for (int i = 0; i < n*m; i++) {
        if (i%m == 0) {
            printf("\n");
        }
        printf("%d ", *p);
        p++;
    }

    p = p_init;

    printf("\n");

    for (int i = 0; i < n*m; i++) {
        if (i/m==i%m) {
            printf("%d", *(p+i));
        }
    }

}

void diagvector(int *p, int dim) {

    int *a;

    a = alocare(dim);

    a = p;

    printf("%d ", *a);
}

void main() {

    int *p, i, j, n, m, dim;

    do {
        printf("Introduceti numarul de linii: ");
        scanf("%d", &n);
    } while (n > 10);
    do {
        printf("Introduceti numarul de coloane: ");
        scanf("%d", &m);
    } while (m > 10);

    dim = n * m;

    p = alocare(dim);

    citireafisare(n, m, p);

    _getch();
}