Final answer:
In programming, to handle negative numbers, variables should be declared as signed. Signed variables use one bit for the sign and the rest for magnitude, allowing them to store both positive and negative values. Unsigned variables, on the other hand, can only hold positive numbers and zero.
Step-by-step explanation:
If your program will ever need negative numbers, you can declare variables to be signed. All bits in signed numbers are used for data, meaning that one bit is typically used to represent the sign of the number (positive or negative), while the rest are used for the magnitude of the number.
Signed variables can hold both positive and negative values, which is essential for many programming tasks that require calculations involving negative numbers. For instance, integers in most programming languages are signed by default. This means if you declare an integer variable without specifying whether it should be signed or unsigned, it will be able to store both positive and negative values.
It's important to note that in the context of computer memory, an unsigned variable can only hold positive numbers and zero. This is because, without a sign bit, all the bits are used for the magnitude, which increases the range of positive numbers that can be represented but excludes negative ones.