# Binary literals

suggest changeThe **0b** prefix can be used to represent Binary literals.

Binary literals allow constructing numbers from zeroes and ones, which makes seeing which bits are set in the binary representation of a number much easier. This can be useful for working with binary flags.

The following are equivalent ways of specifying an `int`

with value `34`

(=25 + 21):

```
// Using a binary literal:
// bits: 76543210
int a1 = 0b00100010; // binary: explicitly specify bits
// Existing methods:
int a2 = 0x22; // hexadecimal: every digit corresponds to 4 bits
int a3 = 34; // decimal: hard to visualise which bits are set
int a4 = (1 << 5) | (1 << 1); // bitwise arithmetic: combining non-zero bits
```

# Flags enumerations

Before, specifying flag values for an `enum`

could only be done using one of the three methods in this example:

```
[Flags]
public enum DaysOfWeek
{
// Previously available methods:
// decimal hex bit shifting
Monday = 1, // = 0x01 = 1 << 0
Tuesday = 2, // = 0x02 = 1 << 1
Wednesday = 4, // = 0x04 = 1 << 2
Thursday = 8, // = 0x08 = 1 << 3
Friday = 16, // = 0x10 = 1 << 4
Saturday = 32, // = 0x20 = 1 << 5
Sunday = 64, // = 0x40 = 1 << 6
Weekdays = Monday | Tuesday | Wednesday | Thursday | Friday,
Weekends = Saturday | Sunday
}
```

With binary literals it is more obvious which bits are set, and using them does not require understanding hexadecimal numbers and bitwise arithmetic:

```
[Flags]
public enum DaysOfWeek
{
Monday = 0b00000001,
Tuesday = 0b00000010,
Wednesday = 0b00000100,
Thursday = 0b00001000,
Friday = 0b00010000,
Saturday = 0b00100000,
Sunday = 0b01000000,
Weekdays = Monday | Tuesday | Wednesday | Thursday | Friday,
Weekends = Saturday | Sunday
}
```

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