Counting a vector of strings

[wookietookie]

I have this exercise: the program receives as an input a .txt file where in the first line there is number of entries, the second line has the minimum number of times a word has to be repeated to be considered and the following lines have all the words. I have to count how many times a word is repeated and then print the word(s).

e.g.
input:

6
2
hey
tomorrow
hey
what
then
then

output:

hey
then

I worked like this: I put the input strings in vector<string> wordList, then in the seek function I count how many times a word is repeated in the vector and insert in the "counting" vector the word and how many times it is repeated. With the sort I sort them so that the number of times is in descending order and in the final loop I print out i < times words.

Result: segmentation fault. I've put some flags around and it seems that the last for loop don't work, as the program runs fine until there.

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

struct wordFreq 
{
	int times;
	string words;
};

void seek (vector<wordFreq> &counting, vector<string> &wList, int dim)
{
	for (int i = 0; i < dim; ++i)
	{
		int count = 0;
		wordFreq word;

		for (int j = 0; j < dim; ++j)
		{
			if (wList[i] == wList[j])
				count++;
		}

		for (int k = 0; k < counting.size(); ++k)
		{
			if (wList[i] != counting[k].words)
			{
				word.times = count;
				word.words = wList[i];
				counting.push_back(word);
				break;
			}
		}
	}
}

bool wayToSort (wordFreq left, wordFreq right)
{
	if (left.times > right.times)
		return true;
	else 
		return false;
}

int main()
{
	int dim;
	int times;
	string word;
	vector<string> wordList;
	vector<wordFreq> counting;

	cin >> dim;
	cin >> times;
	
	for (int i = 0; i < dim; ++i) 
	{
		cin >> word;
		wordList.push_back(word);
	}

	seek (counting, wordList, dim);
	sort (counting.begin(), counting.end(), wayToSort);

	for (int i = 0; i < times; ++i)
	{
		cout << counting[i].words << endl;
	}

}

[Moschops]

	for (int i = 0; i < times; ++i)
	{
		cout << counting[i].words << endl;
	}

This makes no sense. You are trying to output the following strings:

counting[0]
counting[1]
counting[2]
...
counting[times - 1]

But counting doesn't have that many elements.

[jlb]

Have you considered using a std::map<sting, int> to do the counting automatically for you? Something like:

#include <iostream>
#include <sstream>
#include <string>
#include <map>

using namespace std;

int main()
{
    std::stringstream sin("6\n2\nhey\ntomorrow\nhey\nwhat\nthen\nthen\n");
    int number_entries;
    int number_occurances_required;

    sin >> number_entries >> number_occurances_required;

    std::string line;
    std::map<std::string, int> freq;

    while(getline(sin, line))
        freq[line]++;


    for(auto& itr : freq)
        if(itr.second >= number_occurances_required)
            std::cout << itr.first << std::endl;

    return(0);
}

[wookietookie]

@jib

No, because the exercise is technically about vectors, it's from a lesson about them.

@Moschops

I don't get it. Does the seek function have any sense at all? Because that should add the elements to the counting vector.

[jlb]

You seem to be unaware of the fact that std::vectors know their sizes.

So the following should really be using that fact:

	for (int i = 0; i < times; ++i)
	{
		cout << counting[i].words << endl;
	}

becoming something like (using C++11 ranged based loops):

   for(auto& itr : counting)
      cout << itr << endl;

or

   for(size_t i = 0; i < counting.size(); ++i)
      cout << counting[i].words << endl;

You should also rework the rest of your program to take this into account.