C++ : Can someone please explain what i am doing wrong here (in the top_three_trend function)? Any help would be greatly appreciated. Heres what I have below:

// Fills the provided vector with the 3 most-tweeted hashtags,

// in order from most-tweeted to least-tweeted.

//

// If there are fewer than 3 hashtags, then the vector is filled

// with all hashtags (in most-tweeted to least-tweeted order).

//

// Must run in O(n) time.

void Trendtracker::top_three_trends(vector &T){

// clear (max 3 each time)

T.clear();

// hold copy of original list

vector copy;

copy = E;

// sort copy

int largest = 0; // index of largest at start

while (largest < copy.size()){

for (int i = 0; i < copy.size(); i++){

if (copy[largest].pop < copy[i].pop){

// swap to first index

Entry temp;

temp = copy[largest];

copy[largest] = copy[i];

copy[i] = temp;

}

}

largest++; // increment index of largest

}

// find top 3 in copy

//

int front = 0; // always first index

int back = copy.size() - 1; // initialized to last index

if (copy.size() >= 3){

back = front + 2;

for (int i = 0; i <= back; i++){

T.push_back(copy[i].hashtag);

}

} else {

for (int i = 0; i < copy.size(); i++){

T.push_back(copy[i].hashtag);

}

}

}

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// Header file

#ifndef TRENDTRACKER_H

#define TRENDTRACKER_H

#include

#include

using namespace std;

class Trendtracker

{

// For the mandatory running times below:

// n is the number of hashtags in the Trendtracker.

public:

// Creates a new Trendtracker tracking no hashtags.

//

// Must run in O(1) time.

Trendtracker();

// Inserts a hashtag (tweeted 0 times) into the Trendtracker.

// If the hashtag already is in Trendtracker, does nothing.

//

// Must run in O(n) time.

void insert(string ht);

// Return the number of hashtags in the Trendtracker.

//

// Must run in O(1) time.

int size();

// Adds 1 to the total number times a hashtag has been tweeted.

// If the hashtag does not exist in TrendTracker, does nothing.

//

// Must run in O(n) time.

void tweeted(string ht);

// Returns the number of times a hashtag has been tweeted.

// If the hashtag does not exist in Trendtracker, returns -1.

//

// Must run in O(n) time.

int popularity(string name);

// Returns a most-tweeted hashtag.

// If the Trendtracker has no hashtags, returns "".

//

// Must run in O(n) time.

string top_trend();

// Fills the provided vector with the 3 most-tweeted hashtags,

// in order from most-tweeted to least-tweeted.

//

// If there are fewer than 3 hashtags, then the vector is filled

// with all hashtags (in most-tweeted to least-tweeted order).

//

// Must run in O(n) time.

void top_three_trends(vector &T);

private:

// A simple class representing a hashtag and

// the number of times it has been tweeted.

class Entry

{

public:

string hashtag;

int pop;

};

// Entries containing each hashtag and its popularity.

vector E;

};

#endif

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