keyword: double

This is used to define a double-precision floating-point number. It is called double because it is twice the size of a float.

The values that can be stored in floating-point numbers are complicated, but generally, a double can store up to 17 significant figures.

See Performance Considerations for things you should watch out for when writing software.

Usage:

double x = 12.345;
double y = -0.12345678912345678;