Question - How is integer represented in memory?

Answered by: Norma Gonzalez  |  Category: General  |  Last Updated: 26-06-2022  |  Views: 630  |  Total Questions: 14

Integers are commonly stored using a word of memory, which is 4 bytes or 32 bits, so integers from 0 up to 4, 294, 967, 295 (232 - 1) can be stored. Below are the integers 1 to 5 stored as four-byte values (each row represents one integer). How integers are stored in memory using two's complement. An integer is a number with no fractional part; it can be positive, negative or zero. In ordinary usage, one uses a minus sign to designate a negative integer. However, a computer can only store information in bits, which can only have the values zero or one. The total memory is organized into number of bytes and each byte is again divided into 8 bits. A bit is the smallest unit in the memory, these bits are the places where the data is stored as 1's and 0's called binary data. In the memory every byte is identified with a number called address. Computers use a fixed number of bits to represent an integer. The commonly-used bit-lengths for integers are 8-bit, 16-bit, 32-bit or 64-bit. Unsigned Integers: can represent zero and positive integers. Signed Integers: can represent zero, positive and negative integers. The appropriate amount of space is allocated given the data type, and the variable is stored in memory just as it is. These are called stack memory and heap memory. Stack memory stores primitive types and the addresses of objects. The object values are stored in heap memory.

http://statmath.wu.ac.at/courses/data-analysis/itdtHTML/node55.html

Integers are commonly stored using a word of memory, which is 4 bytes or 32 bits, so integers from 0 up to 4, 294, 967, 295 (232 - 1) can be stored. Conversely, if only very small integer values are needed, it may be possible to use a smaller number of bytes or even to work with only a couple of bits (less than a byte).

https://www.learncpp.com/cpp-tutorial/signed-integers/

The range of an integer variable is determined by two factors: its size (in bits), and whether it is signed or not. By definition, a 1-byte signed integer has a range of -128 to 127. This means a signed integer can store any integer value between -128 and 127 (inclusive) safely.

https://www.thoughtco.com/definition-of-unsigned-958174

Unsigned Variable Type of Integer An unsigned variable type of int can hold zero and positive numbers, and a signed int holds negative, zero and positive numbers. In 32-bit integers, an unsigned integer has a range of 0 to 232-1 = 0 to 4, 294, 967, 295 or about 4 billion.

https://cs.calvin.edu/activities/books/rit/chapter5/negative.htm

Negative Numbers The simplest is to simply use the leftmost digit of the number as a special value to represent the sign of the number: 0 = positive, 1 = negative. For example, a value of positive 12 (decimal) would be written as 01100 in binary, but negative 12 (decimal) would be written as 11100.

https://www.techopedia.com/definition/23980/float

Float is a term is used in various programming languages to define a variable with a fractional value. Numbers created using a float variable declaration will have digits on both sides of a decimal point. This is in contrast to the integer data type, which houses an integer or whole number.

https://www.cs.utah.edu/~germain/PPS/Topics/unsigned_integer.html

Unsigned Integers. Unsigned Integers (often called "uints") are just like integers (whole numbers) but have the property that they don't have a + or - sign associated with them. Thus they are always non-negative (zero or positive). We use uint's when we know the value we are counting will always be non-negative.

https://www.oreilly.com/library/view/introduction-to-digital/9780470900550/chap2-sec009.html

2. 5 SIGNED AND UNSIGNED NUMBERS. Unsigned binary numbers are, by definition, positive numbers and thus do not require an arithmetic sign. An m-bit unsigned number represents all numbers in the range 0 to 2m − 1. The most significant bit of a binary number is used to represent the sign bit.

https://www.wisegeek.com/what-is-integer-format.htm

An integer format is a data type in computer programming. Data is typed by the kind of information that is being stored, to what accuracy numeric data is stored, and how that information is to be manipulated in processing. Integers represent whole units.

https://en.wikipedia.org/wiki/9,223,372,036,854,775,807

The number 9, 223, 372, 036, 854, 775, 807, equivalent to the hexadecimal value 7FFF, FFFF, FFFF, FFFF16, is the maximum value for a 64-bit signed integer in computing.

http://www.plctalk.net/qanda/showthread.php?t=63100

In general, word is a set of bits. Typically it is 16-bit long in PLC. The word content may be or may be not interpreted as a number. Integer is an unambiguous numerical value format, and also typically it is 16-bit long in PLC.