The signed category of representation uses flag signs to connote negative integers. Unsigned data categories do not use such signs as they can only include zero and all other positive values. The ‘signed’ and ‘unsigned’ distinction is important for a computer application to function properly.

## Key Takeaways

- Signed data is verified with a digital signature, which guarantees the authenticity and integrity of the data.
- Unsigned data does not have a digital signature and is not verified, making it vulnerable to tampering or modification.
- Signed data is commonly used in secure communications, while unsigned data is used in non-critical applications.

**Signed vs Unsigned**

Signed and unsigned pertain to how numbers are represented in computer programming. Unsigned numbers are always positive, they can express bigger positive values. Signed numbers can be either positive or negative, they have an equal distribution of positive and negative values.

In computer programming, these ‘signed’ and ‘unsigned’ categories refer to variables that can contain certain types of integers. In the coding context, the former category can hold both types of integers. In contrast, the latter category can solely encompass the number zero and the entire list of positive integers.

**Comparison Table**

Parameters of Comparison | Signed | Unsigned |
---|---|---|

Values Included | Signed data categories include both positive and negative integers. | Unsigned data categories include only zero and other positive integers. They cannot include negative integers. |

Magnitude | Signed integers have a smaller magnitude than their unsigned counterparts of the same range. | Unsigned integers have a greater magnitude than their signed counterparts of the same range. |

Flag Sign | Signed data types use a flag sign before the negative numbers they represent. | Unsigned data types do not use a flag sign before numbers, as they only represent positive integers. |

Process of Identification | The signed data containers use the leftover bit. | The unsigned data containers use the leading bit of a value. |

Range in Char | Signed integers range from -128 to 127 in chars. | Unsigned integers range from 0 to 255 in chars. |

Representation Method | 1’s complement form, 2’s complement form, and the sign-magnitude form methods can represent signed binary variables. | Unsigned binary variables do not have a preceding sign or symbol; thus, only one representation method exists for such binary variables. |

Unambiguous Method of Representation | 1 out of 3 possible methods of representation is unambiguous. | The only method of representation available is an unambiguous one. |

**What is Signed?**

Signed number representation is the categorization of positive as well as negative integers. Signed data groupings comprise numbers on both sides of the number line. The negative numbers are distinguished from the positive ones by flag signs.

Signed number groupings are used in computer programming. There are three methods of representing signed data sets. Under the sign-magnitude method, one bit is reserved for the sign symbol. This makes it an ambiguous method.

Similarly, the 1’s complement method is an ambiguous representation of signed integers. The 2’s complement method is the only unambiguous method that can be used to represent these integers.

Such data types have been extensively used in developing programming languages like C and C+.

**What is Unsigned? **

Unsigned data categorizations are essentially classifications of positive integers. They exclusively contain positive values. Zero is also a part of the unsigned categorization. Unsigned data sets do not have flag signs preceding the included integers, as all the values are positive.

Like signed binary integers, unsigned ones are also used in programming. C++, C#, and other programming languages use these data sets. In char, unsigned binary integers range from 0 to 255.

Unsigned data types can only represent the binary number’s magnitude. This connotes that each number has only one binary equivalent form.

Hence, this form of representation is called the unambiguous method of representation. Moreover, unsigned variables have twice the magnitude of their signed counterparts of the same range.

**Main Differences Between Signed and Unsigned**

- The main difference between signed and unsigned data types is that the former allows the user to represent both positive and negative numbers. At the same time, the latter is used to represent zero and other positive numbers. Unsigned data types cannot represent negative numbers. They can be exclusively used for positive integers.
- Although similar types of signed and unsigned variables have the same range, the latter represents a larger magnitude than the corresponding signed variable.
- A signed data categorization uses a flag sign before the negative numbers it represents. The unsigned data category uses no such flag sign, as it only represents positive numbers.
- The two categories also differ in terms of their ranges in the context of char. Signed integers range from -128 to 127 chars, while unsigned integers range from 0 to 255 chars.
- Another difference between the two is the method of identification each uses. The leading bit of a given value is used as a part of the value by the unsigned data category to identify whether the number is positive or negative. Alternatively, signed data types use the leftover bit to make the same identification.
- 1’s complement method, 2’s complement method, and the sign-magnitude form method can be used to represent signed variables, as some binary variables have a negative flag sign. While the binary variables of the unsigned category solely represent their magnitudes as they are all positive integers.
- Signed binary integers have three possible representation techniques but only one unambiguous representation method, while unsigned binaries have one method of representation that is unambiguous.

**References**

- https://ieeexplore.ieee.org/abstract/document/6606625/
- https://link.springer.com/chapter/10.1007/978-3-540-28628-8_8
- https://www.cs.umn.edu/sites/cs.umn.edu/files/tech_reports/14-006.pdf

Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.