What is 1 << 0?

Q: What does << mean in C code?

The << operator shifts the left-hand value left by the (right-hand value) bits. Your example does nothing! 1 shifted 0 bits to the left is still 1. However, 1 << 1 is 2, 1 << 2 is 4, etc.

Q: What is << In bitwise?

The bitwise shift operators are the right-shift operator ( >> ), which moves the bits of an integer or enumeration type expression to the right, and the left-shift operator ( << ), which moves the bits to the left.

Q: What does bit shifting by 0 do?

1 in binary is 0001 , then bitshifting it by 0 won't do anything, which aligns with what you observed. So any number x << 0 is equivalent to x * 2^0 , which is x * 1 , which is just x .

Tags:

c++

syntax

bit-manipulation

 enum     {       kFlag_FPS         = 1 << 0,       kFlag_Help        = 1 << 1,       kFlag_RedBlue3D   = 1 << 2,     }

I am trying to understand what this code is I don't quite know what:

1 << 0

means?

Any help is greatly appreciated!

874

asked Aug 13 '13 17:08

CodeDoctorJL

2 Answers

From MSDN - Shift Operators: >> and <<

The left-shift operator causes the bit pattern in the first operand to be shifted to the left by the number of bits specified by the second operand. Bits vacated by the shift operation are zero-filled. This is a logical shift instead of a shift-and-rotate operation.

This means that the user is taking the bits value of 1 and shifting the bits to the left based on the right number.

That means that in this case, their values will look like this in binary.

1 << 0 = `0000 0001` 1 << 1 = `0000 0010` 1 << 2 = `0000 0100`

The first shift is not necessary, but it looks more consistent with the rest.

115

answered Oct 02 '22 00:10

Caesar

1 << 0 is 1 shifted to the left by 0 positions, which is just 1.

answered Oct 01 '22 23:10

1''

Related questions
                            
                                Checking for a null object in C++
                            
                                Convert wchar_t to char
                            
                                C++ fastest way to clear or erase a vector
                            
                                Casting int to bool in C/C++
                            
                                std::unique_ptr usage
                            
                                Remove First and Last Character C++
                            
                                Does C/C++ offer any guarantee on minimal execution time?
                            
                                Getters and Setters. Is there performance overhead?
                            
                                Using default in a switch statement when switching over an enum
                            
                                How to enable gdb pretty printing for C++ STL objects in Eclipse CDT?
                            
                                Is there a C++ equivalent to getcwd?
                            
                                Boost PropertyTree: check if child exists
                            
                                std::chrono and cout
                            
                                Emacs C++-mode incorrect indentation?
                            
                                Forcing GCC to compile .cpp file as C
                            
                                How does C++ linking work in practice? [duplicate]
                            
                                Comma omitted in variadic function declaration in C++
                            
                                How do I recursively create a folder in Win32?
                            
                                When should I use decltype(x) instead of auto to declare the type of a variable?
                            
                                Qt: is removing QList elements while iterating using foreach macro possible?

Donate For Us

If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!

Donate Us With