In computing, signed number representations are required to encode negative numbers in binary number systems.
In mathematics, negative numbers in any base are represented by prefixing them with a − sign. However, in computer hardware, numbers are represented in bit vectors only without extra symbols. The four best-known methods of extending the binary numeral system to represent signed numbers are: sign-and-magnitude, ones' complement, two's complement, and excess-K. Some of the alternative methods use implicit instead of explicit signs, such as negative binary, using the base −2. Corresponding methods can be devised for other bases, whether positive, negative, fractional, or other elaborations on such themes. In practice the representation most generally used in current computing devices is two's complement, although there is no definitive criterion by which any of the representations is universally superior.
Read more about Signed Number Representations: Sign-and-magnitude Method, Ones' Complement, Two's Complement, Excess-K, Base −2, Comparison Table, Other Systems
Famous quotes containing the words signed and/or number:
“My fellow Americans, I am pleased to tell you today that I’ve signed legislation which outlaws Russia forever. The bombing begins in five minutes.”
—Ronald Reagan (b. 1911)
“In view of the fact that the number of people living too long has risen catastrophically and still continues to rise.... Question: Must we live as long as modern medicine enables us to?... We control our entry into life, it is time we began to control our exit.”
—Max Frisch (1911–1991)