算術(shù)/邏輯移位的實(shí)現(xiàn)。

2019-11-10 20:07:49

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/*.c文件聲明：算術(shù)/邏輯移位的實(shí)現(xiàn)。C語(yǔ)言的移位要取決于數(shù)據(jù)類型：對(duì)于無(wú)符號(hào)數(shù)，左移時(shí)右側(cè)補(bǔ)0（相當(dāng)于邏輯移位）對(duì)于無(wú)符號(hào)數(shù)，右移時(shí)左側(cè)補(bǔ)0（相當(dāng)于邏輯移位）對(duì)于有符號(hào)數(shù)，左移時(shí)右側(cè)補(bǔ)0（叫算術(shù)移位，相當(dāng)于邏輯移位）對(duì)于有符號(hào)數(shù)，右移時(shí)左側(cè)補(bǔ)符號(hào)位（如果正數(shù)就補(bǔ)0，負(fù)數(shù)就補(bǔ)1，叫算術(shù)移位），原來(lái)符號(hào)位的值會(huì)被移到下一位！PRintf中的%d表示：十進(jìn)制整數(shù)。由下例可知，它可以自動(dòng)識(shí)別該數(shù)是有符號(hào)數(shù)還是無(wú)符號(hào)數(shù)。*/#include<stdio.h>int main(void){short signed_bit_8 = 0xffff;//直接將該變量塞爆，無(wú)報(bào)錯(cuò)。直接寫(xiě)該內(nèi)存空間。unsigned short unsigned_bit_8 = 0xffff;printf("signed_bit_8 = %d/n",signed_bit_8);//out_put = -1printf("unsigned_bit_8 = %d/n",unsigned_bit_8);//out_put = 65535signed_bit_8 = signed_bit_8 << 1;unsigned_bit_8 = unsigned_bit_8 << 1;printf("signed_bit_8 = %d/n",signed_bit_8);//out_put = -2printf("unsigned_bit_8 = %d/n",unsigned_bit_8);//out_put = 65534signed_bit_8 = 0xffff;unsigned_bit_8 = 0xffff;signed_bit_8 = signed_bit_8 >> 1;unsigned_bit_8 = unsigned_bit_8 >> 1;printf("signed_bit_8 = %d/n",signed_bit_8);//out_put = -1printf("unsigned_bit_8 = %d/n",unsigned_bit_8);//out_put = 32767return 0;}

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