C++11 - Error in calculating mode in a vector of numbers

Question

I'm working on a program that, given a list of values (doubles) from an input file, sorts them in ascending order and calculates the mode, and print the result in an output file. This is what I came up with so far.

What it should do is assign the mode to the xth element of the vector, the one that produces the greater value for current, but when I run this program the mode is always equal to the last element of the vector.

I just can't figure out what mistake I'm doing, because in my mind it seems perfectly logical.

Any help is greatly appreciated.

#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <fstream>
using namespace std;

int main()
{
    ifstream iFile("inp.txt");
    if(!iFile)
    {
        cout << "Error input!" << endl;
        return -1;
    }

    ofstream oFile("out.txt");
    if(!oFile)
    {
        cout << "Error output!" << endl;
        return -1;
    }

    double data;
    vector<double> list;

    while(iFile >> data)
    {
        list.push_back(data);               //put the elements in a vector
        sort(list.begin(), list.end());     //and sort them in ascending order
    }

    for(int m = 0; m < list.size(); ++m)    //this is just
    {                                       //to verify
        oFile << list[m] << endl;           //that the elements
    }                                       //are listed in order

    int current = 0;
    int previous = 0;
    int mode = 0;
    for(int x = 0; x < list.size(); ++x)        //select an element of the vector
    {
        for(int y = 0; y < list.size(); ++y)    //match it against all the other elements of the vector
        {
            if(list[x] == list[y])              //if they're of equal value
            {
                ++current;                      //add 1 to variable "current"
            }
        }

        if(current > previous)                  //if "current" > "previous"
            {
                mode = list[x];                 //set the element "x" (from the first for) of the vector "list" to be the new mode
                current = previous;             //and set current to be the new previous    
            }

        current = 0;                            //reset current to 0
    }

    oFile << "\nmode: " << mode << endl;        //output "mode"

    return 0;
}

Answer 1

Try with

previous = current;

instead of

current = previous;

in the last if, or previous is ever zero and the last x (matching with itself when y is equal to x) generate a current greater than previous (that is zero).

OT: look at this while

while(iFile >> data)
{
    list.push_back(data);               //put the elements in a vector
    sort(list.begin(), list.end());     //and sort them in ascending order
}

There is no need to sort the vector after every single insertion. I suggest you to add in list all the content of the input file and, after, sort the vector. Only one time, only after the last insertion.

Something like

while(iFile >> data)
{
    list.push_back(data);  //put the elements in a vector
}

sort(list.begin(), list.end()); //and sort them only one time