#include <iostream>
#include <fstream>
#include <math.h>
#include <stdio.h>
#include <conio.h>
#define  NATTRS 5 //number of attributes
#define  MAXSZ  1700 //max size of training set
#define  MAXVALUE  10000.0 //the biggest attribute's value is below 10000(int)
#define  K  5

using namespace std;
struct vector {
    double attributes[NATTRS];
    double classlabel;
};
struct item {
    double distance;
    double classlabel;
};
struct vector trSet[MAXSZ];//global variable,the training set
struct item knn[K];//global variable,the k-neareast-neighbour set
int curTSize = 0; //current size of the training set
int AddtoTSet(struct vector v)
{
    if(curTSize>=MAXSZ) {
        cout<<endl<<"The training set has "<<MAXSZ<<" examples!"<<endl<<endl;
        return 0;
    }
    trSet[curTSize] = v;
    curTSize++;
    return 1;
}
double Distance(struct vector v1,struct vector v2)
{
    double d = 0.0;
    double tem = 0.0;
    for(int i = 0;i < NATTRS;i++)
        tem += (v1.attributes[i]-v2.attributes[i])*(v1.attributes[i]-v2.attributes[i]);
    d = sqrt(tem);
    return d;
}
int max(struct item knn[]) //return the no. of the item which has biggest distance(
                           //should be replaced)
{
    int maxNo = 0;
    if(K > 1)
    for(int i = 1;i < K;i++)
        if(knn[i].distance>knn[maxNo].distance)
            maxNo = i;
    return maxNo;
}

double Classify(struct vector v)//decide which class label will be assigned to
                             //a given input vetor with the knn method
{
    double dd = 0;
    int maxn = 0;
    int freq[K];
    double mfreqC = 0;//the class label appears most frequently
    int i;
    for(i = 0;i < K;i++)
        knn[i].distance = MAXVALUE;
    for(i = 0;i < curTSize;i++)
    {
        dd = Distance(trSet[i],v);
        maxn = max(knn);//for every new state of the training set should update maxn
            if(dd < knn[maxn].distance) {
                knn[maxn].distance = dd;
                knn[maxn].classlabel = trSet[i].classlabel;
            }
    }
    for(i = 0;i < K;i++)//freq[i] represents knn[i].classlabel appears how many times
        freq[i] = 1;
    for(i = 0;i < K;i++)
        for(int j = 0;j < K;j++)
            if((i!=j)&&(knn[i].classlabel == knn[j].classlabel))
                freq[i]+=1;
    int mfreq = 1;
    mfreqC = knn[0].classlabel;
    for(i = 0;i < K;i++)
        if(freq[i] > mfreq)  {
            mfreq = freq[i];//mfreq represents the most frepuences
            mfreqC = knn[i].classlabel; //mfreqNo is the item no. with the most frequent
                                         //classlabel
        }
    return mfreqC;
}
void main()
{

    double classlabel;
    double c;
    double n;
    struct vector trExmp;
    int i;
    ifstream filein("d:\\1.txt");
    if(filein.fail()){cout<<"Can't open data.txt"<<endl; return;}
    while(!filein.eof()) {
        filein>>c;
        trExmp.classlabel = c;
        cout<<trExmp.classlabel<<" ";

        for(int i = 0;i < NATTRS;i++) {
        filein>>n;
        trExmp.attributes[i] = n;
        cout<<trExmp.attributes[i]<<" ";
        }

        cout<<endl;
     if(!AddtoTSet(trExmp))
        break;
    }

    filein.close();

    struct vector testv={{142,188,11,1159,0.5513196},17};
    classlabel = Classify(testv);
    cout<<"The classlable of the testv is:    ";
    cout<<classlabel<<endl;
    for(i = 0;i < K;i++)
        cout<<knn[i].distance<<"\t"<<knn[i].classlabel<<endl;
    //cout<<max(knn);
}