strcpy安全函数

char* strncpy(char *dest, const char *src, size_t n){size_t i;for (i = 0; i < n && src[i] != '\0'; i++)dest[i] = src[i];for ( ; i < n; i++)dest[i] = '\0';// 如果*src长度小于n, 需要把后面置空return dest;}