30. 使用realloc分配内存

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

int main()
{
    int *pNumber = (int *)calloc(10, sizeof(int));
    if (!pNumber)
    {
        printf("failed to malloc");
        return -1;
    }
    pNumber = (int *)realloc(pNumber, 25 * sizeof(int));
    for (int i = 0; i < 25; i++)
    {
        *(pNumber + i) = i;
    }
    for (int i = 0; i < 25; i++)
    {
        printf("%d\n", *(pNumber + i));
    }
    printf("before\n");
    free(pNumber);
    printf("after\n");
    pNumber = NULL;
    printf("end\n");
}