清除缓存 c语言_如何用C语言设置，清除和切换单个位？

清除缓存 c语言

Given a number and we have to 1) set a bit, 2) clear a bit and 3) toggle a bit.

给定一个数字，我们必须1)设置一个位，2)清除一个位，3)切换一个位。

1)设置一点 (1) Setting a bit)

To set a particular bit of a number, we can use bitwise OR operator (|), it sets the bits – if the bit is not set, and if the bit is already set, bit’s status does not change.

要设置数字的特定位，我们可以使用按位或运算符( | )，它设置位–如果未设置位，并且如果该位已设置，则位的状态不会改变。

Let suppose there is a number num and we want to set the X^th bit of it, then the following statement can be used to set X^th bit of num

让我们假设有一个数NUM，我们要设置X的^第这一点，那么下面的语句可以用来设置X的num ^个位

    num |= 1 << x;

2)清除一点 (2) Clearing a bit)

To clear a particular bit of a number, we can use bitwise AND operator (&), it clears the bit – if the bit is set, and if the bit is already cleared, bit’s status does not change.

要清除数字的特定位，我们可以使用按位AND运算符(＆)，清除该位–如果该位已设置，并且如果该位已被清除，则位的状态不会更改。

Let suppose there is a number num and we want to clear the X^th bit of it, then the following statement can be used to clear X^th bit of num

让我们假设有一个数NUM，我们要清除的^第 X的这一点，那么下面的语句可以用于清除X的num ^个位

    num &= ~(1 << x);

3)切换一点 (3) Toggling a bit)

To toggle a particular bit of a number, we can use bitwise XOR operator (^), it toggles the bit – it changes the status of the bit if the bit is set – it will be un-set, and if the bit is un-set – it will be set.

要切换某个数字的特定位，我们可以使用按位XOR运算符(^)，它会切换该位–如果该位被设置，它将更改该位的状态–将被取消设置，并且如果该位未被设置， -set –将被设置。

Let suppose there is a number num and we want to toggle the X^th bit of it, then the following statement can be used to toggle X^th bit of num

让我们假设有一个数NUM，我们要切换X的^第这一点，那么下面的语句可以用来切换^第 X NUM位

    num ^= 1 << x;

Consider the following code – Here, we are performing all above mentioned operations

考虑以下代码–在这里，我们正在执行上述所有操作

#include <stdio.h>
int main(){//declaring & initializing an 1 byte number
/*
num (hex) = 0xAA
its binary = 1010 1010
its decimal value = 170
*/
unsigned char num = 0xAA;
printf("num = %02X\n", num);
//setting 2nd bit
num |= (1<<2);
//now value will be: 1010 1110 = 0xAE (HEX) = 174 (DEC)
printf("num = %02X\n", num);
//clearing 3rd bit
num &= ~(1<<3);
//now value will be: 1010 0110 = 0xA6 (HEX) = 166 (DEC)
printf("num = %02X\n", num);
//toggling bit 4th bit
num ^= (1<<4);
//now value will be: 1011 0110 = 0xB6 (HEX) = 182 (DEC)
printf("num = %02X\n", num);
//toggling bit 5th bit
num ^= (1<<5);
//now value will be: 1001 0110 = 0x96 (HEX) = 150 (DEC)
printf("num = %02X\n", num);
return 0;
}

Output

输出量

num = AA
num = AE
num = A6
num = B6
num = 96

Read more...

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翻译自: https://www.includehelp.com/c/how-to-set-clear-and-toggle-a-single-bit-in-c-language.aspx

清除缓存 c语言