C編程中的8位、16位、32位整數的分解與合並
阿新 • • 發佈：2019-03-24
tdi code 比較 技術分享 size 指針 alt image amp 在單片機的編程中對於8位、16位、32位整數的分解與合並用的比較多，今天做了簡要學習，後面還需要加以總結。
練習在VC++6.0編程環境中進行，源程序：
#include <stdio.h>
#include "string.h"
int main(int argc, char argv[])
{
unsigned int Data_Uint32=0x12345678;
unsigned short int Data_Uint16_1,Data_Uint16_2;
unsigned char Data_Uint8_1,Data_Uint8_2,Data_Uint8_3,Data_Uint8_4; struct StructByte8{
unsigned char Byte01:1;
unsigned char Byte02:1;
unsigned char Byte03:1;
unsigned char Byte04:1;
unsigned char Byte05:1;
unsigned char Byte06:1;
unsigned char Byte07:1;
unsigned char Byte08:1;
} Test1;
unsigned char C1[]="A";
unsigned short int p16=(unsigned short int *)(&Data_Uint32);//定義16位的指針將32位地址強制轉為16位，高位丟棄取低位
printf("32位整數：0x%x\n",Data_Uint32); printf("-------------------通過指針運算-------------------\n"); Data_Uint16_2p=*(unsigned short int *)p16; Data_Uint16_1p=*((unsigned short int *)p16+1); printf("轉換後的16位整數：0x%x,0x%x\n",Data_Uint16_1p,Data_Uint16_2p); Data_Uint8_1= *(unsigned char *)p16; Data_Uint8_2= *((unsigned char *)p16+1); Data_Uint8_3= *((unsigned char *)p16+2); Data_Uint8_4= *((unsigned char *)p16+3); printf("轉換後的8位整數：0x%x,0x%x,0x%x,0x%x\n",Data_Uint8_1,Data_Uint8_2,Data_Uint8_3,Data_Uint8_4); Data_Uint8_1=0;Data_Uint8_2=0;Data_Uint8_3=0;Data_Uint8_4=0; //直接根據指針取值 //將32位的整數分解成兩個16位的整數,再取低位的16位 //強制轉換，丟棄高位的16位 //32位轉16位 Data_Uint16_1=(unsigned short int)(Data_Uint32>>16); Data_Uint16_2=(unsigned short int)Data_Uint32; //32位轉8位 Data_Uint8_1= (unsigned char)(Data_Uint32>>24); Data_Uint8_2= (unsigned char)(Data_Uint32>>16); Data_Uint8_3= (unsigned char)(Data_Uint32>>8); Data_Uint8_4= (unsigned char)Data_Uint32; printf("-------------------通過位運算-------------------\n"); printf("轉換後的16位整數：0x%x,0x%x\n",Data_Uint16_1,Data_Uint16_2); printf("轉換後的8位整數：0x%x,0x%x,0x%x,0x%x\n",Data_Uint8_1,Data_Uint8_2,Data_Uint8_3,Data_Uint8_4); printf("-------------------通過結構運算-------------------\n"); printf("字符A，ASCII為01000001，結構轉換後的內容\n"); memcpy(&Test1, C1, sizeof(Test1)); printf("Test1.Byte08=%d \n",Test1.Byte08); printf("Test1.Byte07=%d \n",Test1.Byte07); printf("Test1.Byte06=%d \n",Test1.Byte06); printf("Test1.Byte05=%d \n",Test1.Byte05); printf("Test1.Byte04=%d \n",Test1.Byte04); printf("Test1.Byte03=%d \n",Test1.Byte03); printf("Test1.Byte02=%d \n",Test1.Byte02); printf("Test1.Byte01=%d \n",Test1.Byte01); Data_Uint8_1=0x89;Data_Uint8_2=0xAB;Data_Uint8_3=0xCD;Data_Uint8_4=0xEF; printf("-------------------通過位運算合並-------------------\n"); Data_Uint16_1 = (unsigned short int)(Data_Uint8_1 << 8) | (unsigned short int)(Data_Uint8_2); Data_Uint16_2 = (unsigned short int)(Data_Uint8_3 << 8) | (unsigned short int)(Data_Uint8_4); Data_Uint32=(unsigned int) (Data_Uint16_1 << 16) | (unsigned int)(Data_Uint16_2); printf("合並前的8位整數：0x%x,0x%x,0x%x,0x%x\n",Data_Uint8_1,Data_Uint8_2,Data_Uint8_3,Data_Uint8_4); printf("合並後的16位整數：0x%x,0x%x\n",Data_Uint16_1,Data_Uint16_2); printf("合並後的32位整數：0x%x\n",Data_Uint32); return 0;
}
輸出：
C編程中的8位、16位、32位整數的分解與合並