char * 指针

int main(void)
{
char *p1 = NULL, *p2 = NULL, *p3 = NULL;

    /* 1. malloc */    p1 = malloc(10);    strcpy(p1, "hello");        printf("p1 = %s\n", p1);    free(p1);    /* 2. calloc */    p2 = calloc(5, 2);    strcpy(p1, "hello");    printf("p2 = %s\n", p1);    free(p2);    /* 3. realloc */    char *new_p = NULL;    new_p = malloc(1);    strcpy(new_p, "hello");    p3 = realloc(new_p, 10);//将new_p指向的内容复制到普新开得空间    printf("p3 = %s\n", p3);    free(p3);    return 0;

}
运行结果：