这段代码错误在哪里，C语言代码

//错误：char s = src[len]; 修改为：char s = src + len - 1;

//错误：d++ = s--; 修改为：*d++ = *s--;

//添加：*d = '\0';
// printf("%s",dest);

#include <stdio.h>
#include <string.h>
#include <malloc.h>
int main()
{
    char* src = "hello,world";
    char* dest = NULL;
    int len = strlen(src);
    dest = (char*)malloc(len);
    char* d = dest;
    char* s = src + len - 1; //char *s = src[len];
    while (len-- != 0)
        *d++ = *s--;         //d++ = s--;
    *d = '\0';               //修改
    printf("%s",dest);

    return 0;
}