Decimal, binary, hex & ASCII numbers conversion table
In mathematics and computing, hexadecimal is a positional numeral system with a radix, or base, of It uses sixteen distinct symbols, most often the symbols "0" –"9" to represent Each hexadecimal digit represents four binary digits, also known as a nibble, which .. π (pi, the ratio of circumference to diameter of a circle). Relationships between various representations of precision. Example conversions from unsigned 8-bit binary to hexadecimal and to decimal. .. For example, if we wish to store the 4 ASCII characters '' which is 0x at . ASCII defines characters, which map to the numbers 0– Unicode defines See below the binary representation of a few characters in ASCII:
Some authors prefer a text subscript, such as decimal and hex, or d and h. In linear text systems, such as those used in most computer programming environments, a variety of methods have arisen: In Intel-derived assembly languages and Modula-2,  hexadecimal is denoted with a suffixed H or h: Ada and VHDL enclose hexadecimal numerals in based "numeric quotes": The Smalltalk language uses the prefix 16r: For PostScript, binary data such as image pixels can be expressed as unprefixed consecutive hexadecimal pairs: Common Lisp uses the prefixes x and 16r.
ASCII, decimal, hexadecimal, octal, and binary conversion table
Thus Hexadecimal numbers can be represented without the x or 16r prefix code, when the input or output base has been changed to Binary, quaternary base-4 and octal numbers can be specified similarly. This format was common on other and now obsolete IBM systems as well.
Occasionally quotation marks were used instead of apostrophes.
Donald Knuth introduced the use of a particular typeface to represent a particular radix in his book The TeXbook. This, for example, is a valid IPv6 address: By contrast, IPv4 addresses are usually written in decimal. There is no universal convention to use lowercase or uppercase for the letter digits, and each is prevalent or preferred in particular environments by community standards or convention. History of written representations[ edit ] Bruce Alan Martin's hexadecimal notation proposal  The use of the letters A through F to represent the digits above 9 was not universal in the early history of computers.
During the s, some installations[ which? The SWAC  and Bendix G   computers used the lowercase letters u, v, w, x, y and z for the values 10 to The positive logic representation defines true as a 1 or high, and false as a 0 or low. If you were controlling a motor, light, heater or air conditioner the boolean could mean on or off. In communication systems, we represent the information as a sequence of booleans: For black or white graphic displays we use booleans to specify the state of each pixel.
BBC Bitesize - GCSE Computer Science - Hexadecimal and character sets - Revision 5
The most efficient storage of booleans on a computer is to map each boolean into one memory bit. In this way, we could pack 8 booleans into each byte. If we have just one boolean to store in memory, out of convenience we allocate an entire byte or word for it. Most C compilers including Keil uVision define: False be all zeros, and True be any nonzero value.
Many programmers add the following macros define TRUE 1 Decimal Numbers Decimal numbers are written as a sequence of decimal digits 0 through 9. The number may be preceded by a plus or minus sign or followed by a Lor U. Lower case l or u could also be used.
The minus sign gives the number a negative value, otherwise it is positive. The plus sign is optional for positive values. Unsigned bit numbers between and should be followed by U.
You can place a L at the end of the number to signify it to be a bit signed number. The range of a decimal number depends on the data type as shown in the following table.
- Hexadecimal and character sets
- Binary and hexadecimal conversions