Thread: deleting elements of a vector

Use the clear member function:

Code:

v.clear();
k.clear();

Originally Posted by strickey

Is there any member function that sorts out a vector

Yes, the sort function:

Code:

#include <algorithm>
#include <vector>

...

std::vector<int> v;

...

std::sort(v.begin(),v.end());

Originally Posted by strickey

or finds index of its greatest element?

Yes, the max_element function:

Code:

#include <algorithm>
#include <vector>
#include <iostream>

...

std::vector<int> v;

...

std::cout << "Index of biggest element is: " << std::max_element(v.begin(),v.end()) << std::endl;
std::cout << "Actual biggest element is: " << *std::max_element(v.begin(),v.end()) << std::endl;

[edit]Just for clarification, the sort and max_element functions are not member functions.[/edit]

Warm recommendation:
http://msdn.microsoft.com/library/de...thmmembers.asp

There's no built-in function that does it in general, but std::unique does it for sorted vectors, so you can just sort the vector by calling std::sort and then use std::unique to remove all duplicates, and finally std::vector::erase to tell the container that elements were removed.

Originally Posted by strickey

Thank you !!!
May I ask if there is a member function that trace elements of same values and discards them all but one?
Thank you one more time

The easiest solution to this is to first sort the container and then call the unique function (not a member function) in combination with the vector's erase member function:

Code:

#include <vector>
#include <algorithm>

...

std::vector<int> v;

...

std::sort(v.begin(),v.end());
v.erase(std::unique(v.begin(),v.end()),v.end());

The reason for combining unique and erase is that unique shuffles the duplicates towards the end of the container and does not remove them. The unique function returns the new logical end of the container (the point where all those duplicates get shuffled to). So you then call the erase member function to remove the elements starting from that logical end position to the true end of the container.

This method will of course destroy the original ordering of elements in the container. If the order is important you will have to come up with something on your own.

[edit]Beaten to the punch! [/edit]

Can you rephrase that?

Check your other post, I may have mislead you a bit... the max_element function returns an iterator (pointer) and not a value you can use (directly) as an array index. I apologize for any confusion. You can use the value returned from max_element along with the distance function to get a value you can use as an index. I posted an example of that in the other post.

[edit]Ha Ha beat you CornedBee! [/edit]

Use std::distance from <iterator> to calculate the distance between this iterator and the begin() iterator.