When to use unsigned values over signed ones?

I was glad to find a good conversation on this subject, as I hadn't really given it much thought before.

In summary, signed is a good general choice - even when you're dead sure all the numbers are positive - if you're going to do arithmetic on the variable (like in a typical for loop case).

unsigned starts to make more sense when:

• You're going to do bitwise things like masks, or
• You're desperate to to take advantage of the sign bit for that extra positive range .

Personally, I like signed because I don't trust myself to stay consistent and avoid mixing the two types (like the article warns against).

In your example above, when 'i' will always be positive and a higher range would be beneficial, unsigned would be useful. Like if you're using 'declare' statements, such as:

#declare BIT1 (unsigned int 1)
#declare BIT32 (unsigned int reallybignumber)

Especially when these values will never change.

However, if you're doing an accounting program where the people are irresponsible with their money and are constantly in the red, you will most definitely want to use 'signed'.

I do agree with saint though that a good rule of thumb is to use signed, which C actually defaults to, so you're covered.