C语言文本字符串转16进制字符串

void ByteToHexStr(char* str, char* dest, int len)
{
    char tmp;
    char stb[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
    for (size_t i = 0; i < len; i++)
    {
        tmp = str[i];
        dest[i * 2] = stb[tmp >> 4];
        dest[i * 2 + 1] = stb[tmp & 15];
    }
    return;
}