C++ Sorting Class Array

Question

C++ Sorting Array Class

I have an array object that record the following..

This is at classone.h

ClassOne
{
string name;
int data;
float valueData;
}

and the constructor are created at classone.cpp

At main.cpp I created ClassOne Array of Size 10

#include "classone.h"

ClassOne cone[10];

Next is i recorded several value to the object

and now ClassOne got 3 objects

cone[0]
name = "hello"
data = 1
valueData = 20

cone[1]
name = "panda"
data = 2
valueData = 15

cone[2]
name = "joe"
data = 3
valueData = 25

What i want to achieve is do a sort that can rearrange this array by valueData highest ascending form so.. it will be

cone[2] then cone[0] then cone[1] ..

but the issue if i use bubble sort , i tried google and find some, they are sorting by e.g int a[]={9,6,5,23,2,6,2,7,1,8};

but i wanna sort by class array object. and re-arrange the value together , how do i achieve this.

So when i cout it will be

-- Highest to lowest --
1) Name: Joe , Data = 3, Value =25
2) Name: Hello , Data =1 , Value = 20
3) Name: Panda, Data = 2, Value = 15

Thanks for all help and guide!!

Answer 1

The easiest way is to use the standard library:

#include <algorithm>

std::sort(cone, cone + 10,
          [](ClassOne const & a, ClassOne const & b) -> bool
          { return a.value < b.value; } );

If you're willing to define a comparison operator globally, you don't even need the lambda:

bool operator<(ClassOne const & a, ClassOne const & b)
{
    return a.value < b.value;
}

std::sort(cone, cone + 10);

Or you could make the comparator a member function. Or you could give the comparator function a custom name and pass that as the third argument of sort. This might be a good idea in the case where the comparison is specific to your situation and not "natural":

bool ValueCmp(ClassOne const & a, ClassOne const & b)
{
    return a.value < b.value;
}

std::sort(cone, cone + 10, ValueCmp);

The last version is useful if you don't have C++11 support (for lambdas, as in the first case), or if you want to reuse the comparator in multiple different situations.