如何將無符號16位和無符號32位整數編碼爲無符號8位存儲器陣列？

Question

我知道如何做位移，但我的價值似乎跑了邊緣，我失去了原來的價值，試圖保留8位的回報。

Answer 1

對於無符號16位整數：

unsigned short val16 = 0x1234; 
unsigned char enc[2]; 
enc[0] = val16 & 0xff;    // stores 0x34 to enc[0] 
enc[1] = val16 >> 8 & 0xff;   // stores 0x12 to enc[1] 

對於無符號32位整數：

unsigned int val32 = 0x12345678; 
unsigned char enc[4]; 
enc[0] = val32 & 0xff;    // stores 0x78 to enc[0] 
enc[1] = val32 >> 8 & 0xff;   // stores 0x56 to enc[1] 
enc[2] = val32 >> 16 & 0xff;  // stores 0x34 to enc[2] 
enc[3] = val32 >> 24 & 0xff;  // stores 0x12 to enc[3] 

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更新

帶小數文字完全相同代碼爲：

unsigned short val16 = 4660;  // 4660 = 0x1234 
unsigned char enc[2]; 
enc[0] = val16 & 255; 
enc[1] = val16 >> 8 & 255; 

和

unsigned int val32 = 305419896; // 305419896 = 0x12345678 
unsigned char enc[4]; 
enc[0] = val32 & 255; 
enc[1] = val32 >> 8 & 255; 
enc[2] = val32 >> 16 & 255; 
enc[3] = val32 >> 24 & 255;