Tag: 位移位

如何在unsigned char中更改4位？

unsigned char *adata = (unsigned char*)malloc(500*sizeof(unsigned char)); unsigned char *single_char = adata+100; 如何更改single_char中的前四位以表示介于1..10（int）之间的值？ 问题来自TCP头结构： Data Offset: 4 bits The number of 32 bit words in the TCP Header. This indicates where the data begins. The TCP header (even one including options) is an integral number of 32 bits long. 通常它的值为4..5，char值类似于0xA0。

C左移64位失败

我在C中有这个代码（仅供学习）： char x; uint64_t total = 0; for(x = 20; x < 30; x++){ total = (((((1 << x) * x) / 64) + 1) * sizeof(uint64_t)); printf("%d – %llu\n", x, total); } 什么是印刷品： 20 – 2621448 21 – 5505032 22 – 11534344 23 – 24117256 24 – 50331656 25 – 104857608 26 – 218103816 […]