Signed integers are a type of integer data type that can represent both positive and negative whole numbers. They are represented using a fixed number of bits, typically 8, 16, 32, or 64 bits, depending on the computer architecture and the programming language.
The most significant bit (MSB) is used to indicate the sign of the integer value, with a value of 0 representing a positive number and a value of 1 representing a negative number. The remaining bits are used to represent the magnitude of the integer value.
For example, in a 8-bit signed integer, the first bit is used as the sign bit, while the remaining 7 bits are used to represent the magnitude of the value. This allows signed integers to represent a range of values between -2^(n-1) to 2^(n-1) - 1, where n is the number of bits used to represent the integer.
In programming languages, signed integers are usually represented using data types such as "int" or "short int". The size of the data type determines the number of bits used to represent the integer and the range of values that can be represented.