[C++] Benifits of declaring signed/unsigned?

[MtnDew]

Hello Dev-Spot,

Why is it beneficial to me to declare a variable being signed or unsigned?

Example:

unsigned short int age; // Declare a variable named age, of type SHORT INT that only accepts positive input.

Thanks,
-MtnDew

[tylerfb11]

The only time that this is nessesary is when you are using varibles that are larger than normal ints, or ones that are only allowed to have positive values and such. If you are simply useing a normal interger, it's really just a formality and it's up to you whether or not you bother doing it.

-Tyler

[Theo]

Yup.
I'll just say it loud and clear:
The benefit of making a variable unsigned is that it can store bigger positive values.
If you don't know the bad side is that it will no longer be able to store negative values.

Cheers,
Theo

[laserlight]

There are operations that, done with signed integer types, can result in implementation defined behaviour, but that result in well defined standard behaviour for unsigned integer types.

[bitt3r0blivion]

Yeah, unsigned are good for getting larger numbers without having to use a larger variable if you know you aren't going to use negative numbers. But a little warning, I wouldn't use unsigned variables in for loops in cases like this

<code>
vector<int> v;

for(unsigned int i = v.size();i<0;i--)
{
    //blah
}
</code>

just because the number will never go negative, i ran into some trouble when i was trying to write a vector class. Just be careful you aren't making silly logic mistakes like that. Other than that there aren't any downfalls to using unsigned variables.

[laserlight]

bitt3r0blivion, I think you meant:

Code:

vector<int> v;

for(unsigned int i = v.size();i>0;i--)
{
    //blah
}

But this problem can be avoided with:

Code:

for (vector<int>::size_type i = v.size(); i-- > 0;)
{
    //blah
}