code> uint8_t 是 unsigned char 的别名，iostreams对于打印字符而不是格式化数字的字符有特殊重载。

uint8_t is an alias for unsigned char, and the iostreams have special overloads for chars that print out the characters rather than formatting numbers.

转换为整数会禁止此操作。

The conversion to integer inhibits this.