# how to check the length of an array

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# how to check the length of an array

Posted 01 February 2008 - 03:58 AM

Hello,
I want to check the length of an array say ARR[100]. Lets assume that after some computations it has 30 values stored in it from ARR[0] to ARR[29]. How do i determine its length?. I am typically expecting an answer of 30.
Thanks,
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## Replies To: how to check the length of an array

### #2 AmitTheInfinity

• C Surfing ∞

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## Re: how to check the length of an array

Posted 01 February 2008 - 04:32 AM

prads, on 1 Feb, 2008 - 04:28 PM, said:

Hello,
I want to check the length of an array say ARR[100]. Lets assume that after some computations it has 30 values stored in it from ARR[0] to ARR[29]. How do i determine its length?. I am typically expecting an answer of 30.
Thanks,

one way could be to keep a counter which will be incremented every time you add a value in array. in another way you can initialize array with some value which you expect never to occur after calculations. and after you finish with your computation, just run a loop till you get that value, the loop counter will give you the length.

I think first way can be good enough for you as second looks like additional logic to be added. I can't think of any other good logic for this right now.

### #3 no2pencil

• Professor Snuggly Pants

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## Re: how to check the length of an array

Posted 01 February 2008 - 05:35 AM

When you init your array, clean it out.

```char ARR[100];
int i=0;

for(i=0;i<=100;i++) {
ARR[i]='\0';
}

```

Now that it's empty, every time that you write a value to ARR, you can check for '\0', & you know you've hit the end of your input.