QuickSort

Hi,
I want to quick sort array of strcutures. can anyone provide me a sample code.

Thanks in advance
Vidhu

Quote:

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Originally Posted by vidhu

Hi,
I want to quick sort array of strcutures. can anyone provide me a sample code.

Thanks in advance
Vidhu

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Any reason why it must be quicksort?

Regards,

Paul McKenzie

In addition....what kind of array? Old-style C array? STL 'vector'?

Its old style C array

Quote:

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Originally Posted by vidhu

Its old style C array

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That still leaves Paul's question...

Currently I am using bubble sort. Which is veryslow when the array size is very large.If around 1-2 million or array elements are there. It takes **** of the time to sort it. so i need to fast up the sorting process. So I want to remove bubble sort and replac eit with quick sort

Bubble-sort is O(N²) while quick-sort is O(N log N).

Now if you have an array of structures, even if it's not a vector you can treat it as one and use STL std::sort.

std::sort is actually often quicker than qsort because of its nature as a template allows means the compiler can often inline the predicate.

If you have an array rather than a vector, pass the address of the first element as the first parameter of std::sort, and "one-past-the-last-element" as the second parameter. Thus:

Code:

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T* begin = &myArray[0]; // = myArray if myArray is an array not a vector
T* end = begin + arraySize; // = myArray.size() if myArray is a vector.

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