二级指针动态数组,模拟指针数组

创建二级指针动态数组,模拟指针数组。里面存放键盘输入的字符串，回车键确定输入，-1为退出条件。

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

int main(void)
{
    char **p = NULL;
    char **prev = NULL;
    int count = 0;
    char buf[1024] = {
   0};
    int i;
    int val;

    while (1) {
        printf("input string\n");
        scanf("%s", buf);

        if (!strncmp("-1",buf, 2))
            break;

        prev = p;
        p = (char **)malloc((count + 1) *sizeof(char *));
        if (NULL == p) {
            free(prev);
            val = -1;
            goto err1;
        }
        memcpy(p, prev, count * sizeof(char *));
        free(prev);

        p[count] = (char *)malloc(strlen(buf) + 1);
        if (NULL == p[count]) {
            val = -1;
            goto err2;
        }

        memcpy(p[count], buf, strlen(buf) + 1);

        count++;
    }
    val = 0;
    for(i = 0; i < count; i++)
        printf("p[%d] =  %s\n", i, p[i]);

err2:
    free(p);

err1:    
    for(i = 0; i < count; i++)
        free(p[i]);

    return val;
}