indentifier question

[masiht]

hello I have a question,
when do we use
double value=0.0;

and when do we use
double value;


or what is the difference ?

[helios]

The former initializes value to zero, the latter doesn't.

[masiht]

do you mean the value is constant as zero
what if the user input something else

[helios]

"Initializing" means "setting something to some initial value". It doesn't mean "permanently setting something to some initial value".

[masiht]

do you mean that in this case the value cannot be less than zero ??
int a=0;

?

[Zhuge]

No helios means it sets the value to zero. Nothing more, nothing less. It can be changed because it is not a constant.

[masiht]

what is the use to assign a value for it, altough we know that the users are going to change it ?

[helios]

That's not always a certainty.
Example:

int a=0, average=0;
for (;v[a]!=0;a++)
    average+=v[a];
average/=a;

[masiht]

I didn't get . please explain in words