# Data types and variables

DPUSER knows about 6 different data types:- integer numbers
- real numbers
- complex numbers
- up to 3-dimensional matrices
- strings
- string arrays

`print acos(2)`, the result will not be integer (which would not make sense), but a complex number. Complex numbers can be constructed by appending an

`i`(without spaces) to a number:

Strings are defined by embracing in double quotes:variable = 1 + 2i

Variable names can include any letter in the range [a-zA-Z] and numbers [0-9] but must not begin with a number. Variables are created on the fly by assigning a value to them. If you supply a value to an already existing variable, it is overwritten:variable = "This is a string".

n = 1 // n is an integer numbern++ // n is still integer with value 2n = sqrt(n) // n now is a real numbern = -(n^2) // n is still a real number with value -2.0n = n^(1/2) // n now is a complex numbern = "a string" // n is a string with value "a string"n = fits(100, 100) // n is now a matrix with 100x100 elements