What is the difference between << and >> in c++

The << and >> in C are bit shift operators, used for bitwise left shift and bitwise right shift of integers respectively. The left shift operator (<<) shifts the binary representation of an integer to the left, filling empty bits with the sign bit or 0. The right shift operator (>>) shifts the binary representation of an integer to the right, filling empty bits with the sign bit or 0.

##The difference between << and >> in C

<< in C (left shift operator) and >> (right shift operator) are bitwise operators used to shift signed or unsigned integers bitwise. The main difference between them is the direction of movement.

Left shift operator (<<)

Left shift operator << Shifts the binary representation of an integer to the left by the specified number of places. When the integer is a signed integer, the vacated bits are filled with sign bits (0 for positive numbers, 1 for negative numbers); when the integer is an unsigned integer, the vacated bits are filled with 0s.

Right shift operator (>>)

Right shift operator >> Shifts the binary representation of an integer to the right by the specified number of places. For signed integers, the sign bit is copied into the vacated bit, thus preserving the sign of the number. For unsigned integers, vacated bits are filled with 0s.

Usage

The left shift operator is typically used to multiply an integer by a power of 2 because it is equivalent to adding 0 in the binary representation.

int x = 5; // 二进制：101
x << 2; // 二进制：10100 (等效于 x * 2^2)

The right shift operator is commonly used to divide an integer by a power of 2 because it is equivalent to removing 0 in the binary representation.

int y = 20; // 二进制：10100
y >> 2; // 二进制：101 (等效于 y / 2^2)

Example

The following table compares the effect of using << and >> to perform displacement operations on signed and unsigned integers:

OperationSigned integerUnsigned integer2020-20-20##5 >> 2-5 >> 2

5 << 2
-5 << 2
1	1
-2	2147483646

Note:

For unsigned integers, the result of the right shift operation is always a positive number.

• For signed integers, the result of the right shift operation depends on the sign bit.

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