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size of array?

 
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size of array?
marla
post 22 Nov, 2005 - 08:01 PM
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i was trying to use

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int myLength = sizeof(myArray);

it is an array of unsigned integers. how can i find out how many items are in the array?
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Mrafcho001
post 22 Nov, 2005 - 08:04 PM
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sizeof(array) will return the size of the array not how many items are in the array.
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marla
post 22 Nov, 2005 - 08:49 PM
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umm ok ... so can you possibly point me in the direction of ascertaining the ammount of items in my array without using a loop ...
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Nova Dragoon
post 22 Nov, 2005 - 08:58 PM
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well if you know how big your array is in bytes, and you know how big one integer is sizeof(int) i think will work, you can divide.
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marla
post 22 Nov, 2005 - 09:22 PM
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the array is constantly being changed. i do not know the size of the array. i just want to find out the number of elements in the array.
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Dark_Nexus
post 22 Nov, 2005 - 11:12 PM
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sizeof(myArray) should return the total size of the array in bytes. knowing this, and that the array is totally composed of integers and that each integer is 4 bytes, you can figure out how many items are in the array.

sizeof(myArray) / sizeof(int) = # of items in the array.
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Amadeus
post 23 Nov, 2005 - 06:44 AM
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Are you using c or c++? If C++, then you should probably use vectors for storing a variable number of elements. Even if you are unable to use vectors, that array must be getting resized in your code somewhere...you should be able to determine the new number of elements using the information used to resize the array.
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marla
post 23 Nov, 2005 - 12:58 PM
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using c. sizeof(myArray) / sizeof(int) worked out great, thanks!
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microchip
post 23 Nov, 2005 - 01:13 PM
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Doesn't sizeof only work at compile time?

So if you use dynamic memory allocation, you can't use this. You'll have to record the length yourself.
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Dark_Nexus
post 23 Nov, 2005 - 03:42 PM
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the sizeof() keyword is called everytime the compiler encounters it, or it is replaced with a known constant. either way, it will work during runtime.
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microchip
post 24 Nov, 2005 - 07:12 AM
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Cool, didn't know that!
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jaredolympia
post 24 Nov, 2005 - 09:42 AM
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[/CODE]arraySize = sizeof(array)/sizeof(array[0]);[CODE]
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