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SXEmacs supports two numeric data types: integers and floating point numbers. Integers are whole numbers such as -3, 0, #b0111, #xFEED, #o744. Their values are exact. The number prefixes ‘#b’, ‘#o’, and ‘#x’ are supported to represent numbers in binary, octal, and hexadecimal notation (or radix). Floating point numbers are numbers with fractional parts, such as -4.5, 0.0, or 2.71828. They can also be expressed in exponential notation: 1.5e2 equals 150; in this example, ‘e2’ stands for ten to the second power, and is multiplied by 1.5. Floating point values are not exact; they have a fixed, limited amount of precision.
SXEmacs can be compiled to use a multi-precision arithmetic library with the –enable-ent switch. Currently the MP-libraries GMP, BSD-MP, MPFR and MPC are supported. We have a dedicated section for this case, See Enhanced Number Types.
| • Integer Basics: | Representation and range of integers. | |
| • Float Basics: | Representation and range of floating point. | |
| • Predicates on Numbers: | Testing for numbers. | |
| • Comparison of Numbers: | Equality and inequality predicates. | |
| • Numeric Conversions: | Converting float to integer and vice versa. | |
| • Arithmetic Operations: | How to add, subtract, multiply and divide. | |
| • Rounding Operations: | Explicitly rounding floating point numbers. | |
| • Bitwise Operations: | Logical and, or, not, shifting. | |
| • Math Functions: | Trig, exponential and logarithmic functions. | |
| • Random Numbers: | Obtaining random integers, predictable or not. |
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