# C - 64-bit real number: double

64-bit real number and his value range: from - 1.7 × 10 on 308 to +1.7 × 10 on 308 and it has 15 digit precision. if it is used to store integers the biggest integer what can store without rounding is 2 on 53. 64-bit real number is stored the following way: 1bit sign, 8bit exponent a 23bit mantissa.## double

### Description

`double`

**Note:**In C like languages the data type size may be different depending on compiler and architecture, we show only one standard look.

### Examples

## C

64-bit real number the possible of use:```
double x = 3.14159265359; // x = 3.14159265359
double y = 123456789; // y = 123456789.0
y =(double)(x * y); // y = 387850941.35821074
```

you can find it in the following collections: real numbers | numbers | data types

64-bit real number in another programming language:

Differences to: