Stl sorting question....

[David1909]

I have vector <Class> array, which contain a sequence of class instances, now could I sort the array accoding to the member value of class?


Thanks

[jfaust]

You need to define your own predicate. Check out this thread.

edited: fixed link
http://www.codeguru.com/forum/showthread.php?s=&threadid=199819

Jeff

[David1909]

But, how to define my own predicate, could you give a example for following code? thanks:

class Me
{
int m_x;

public:

int GetX()
{
return m_x;
}

void SetX(int x)
{
m_x=x;
}
};
void main()
{

vector<Me> ArrayMe;
for(int i=0; i<10; i++)
{
int x=rand()%10;
Me me;
me.setx(x);
Array.push_back();
}

//here I want ro sort ArrayMe according to m_x value
// how do I do?


}


thanks

[jfaust]

First of all, my link was bad. I fixed it.

Second, a better and easier would be to define operator<.

Try this:


#include <vector>
#include <algorithm>
using namespace std;

class Me
{
int m_x;

public:
int GetX() const
{
return m_x;
}

void SetX(int x)
{
m_x=x;
}

bool operator<(const Me& rhs) const
{
return GetX() < rhs.GetX();
}
};

void main()
{
vector<Me> ArrayMe;
for(int i=0; i<10; i++)
{
int x=rand()%10;
Me me;
me.SetX(x);
ArrayMe.push_back(me);
}

std::sort(ArrayMe.begin(), ArrayMe.end());
}

[David1909]

Thanks it is works!