What is the function of the ~ operator?

Question

Unfortunately, search engines have failed me using this query.

For instance:

int foo = ~bar;

Answer 1

In C and C++, it's a bitwise NOT.

Answer 2

It's called a tilde and it looks like some languages use it as a bitwise NOT: http://en.wikipedia.org/wiki/Tilde#Computer%5Flanguages

Answer 3

Normally it's the Negation operator. What is the Language?

Answer 4

It's called Tilde (for your future searches), and is usually user for bitwise NOT (i.e. the complement of each bit)

Answer 5

bitwise negation, yields the bitwise complement of the operand.

In many programming languages (including those in the C family), the bitwise NOT operator is "~" (tilde). This operator must not be confused with the "logical not" operator, "!" (exclamation point), which in C++ treats the entire value as a single Boolean—changing a true value to false, and vice versa, and that C makes a value of 0 to 1 and a value other than 0 to 0. The "logical not" is not a bitwise operation.

Answer 6

In C, it's the bitwise complement operator. Basically, it looks at the binary representation of a number and converts the ones into zeros and the zeros into ones.

Answer 7

I'm assuming based on your most active tags you're referring to C#, but it's the same NOT operator in C and C++ as well.

From MSDN:

The ~ operator performs a bitwise complement operation on its operand, which has the effect of reversing each bit. Bitwise complement operators are predefined for int, uint, long, and ulong.

Example program:

static void Main() 
{
    int[] values = { 0, 0x111, 0xfffff, 0x8888, 0x22000022};
    foreach (int v in values)
    {
        Console.WriteLine("~0x{0:x8} = 0x{1:x8}", v, ~v);
    }
}

Output:

~0x00000000 = 0xffffffff
~0x00000111 = 0xfffffeee
~0x000fffff = 0xfff00000
~0x00008888 = 0xffff7777
~0x22000022 = 0xddffffdd

Answer 8

In most C-like languages, it is a bitwise not. This will take the raw binary implementation of a number, and change all 1's to 0's and 0's to 1's.

For example:

ushort foo = 42;   // 0000 0000 0010 1010
ushort bar = ~foo; // 1111 1111 1101 0101
Console.WriteLine(bar); // 65493