Usage of ~ in c language

The ~ operator in C language is used for bitwise inversion of binary numbers, that is, 0 becomes 1 and 1 becomes 0. Specific applications include negating bit masks, detecting binary bits, creating one's complement codes, and generating one's complement codes.

Usage of ~ operator in C language

The role of ~ operator

~operator is a bitwise negation operator in C language. It inverts each bit of a binary number, i.e. 0 becomes 1 and 1 becomes 0.

Syntax

<code>~expression</code>

where expression can be any integer type data.

Operation result

~The operation result of the operator is an integer of the same type as expression, and every bit in its binary representation is inverted.

Application scenarios

~Operators are mainly used in the following scenarios in C language:

• Reverse bit mask :Inverting a bitmask produces a mask that is the opposite of the original bitmask. For example: ~0x0F is generated as 0xF0.
• Detecting binary bits: By performing the ~ operation on a number and bitwise ANDing it with another number, you can check whether a specific binary bit of the number is 1. For example: x & ~0x08 checks whether the 3rd bit of x is 0.
• Create one's complement code: For negative numbers, the ~ operator can generate its one's complement code. For example: ~(-5) generates 4.
• Generate one's complement: For negative numbers, the ~ operator can generate its complement. For example: ~(-5) is generated as 3.

Example

#include <stdio.h>

int main() {
    int x = 0x12;

    printf("~x = %x\n", ~x);   // 输出: 0xED
    printf("~x & 0x08 = %x\n", ~x & 0x08);  // 输出: 0x00 (检查 x 的第3位是否为0)

    return 0;
}

Note:

~ operator has higher precedence than bitwise AND (& ) and bitwise OR (|) operators.

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