Java Code For Nearest Neighbor classifier

Java Code For Nearest Neighbor classifier

import java.io.*;

importjava.util.*;

importjava.math.*;

public class KNN

{

Scanner src=new Scanner(System.in);

introwcount=0,colcount;

String f[][];

intcolvar=0;

float[] newcol;

float[] requirement;

String[] req;

double[] dist;

intT,pos;

float min=0.0f,max=0.0f;

void display()

{

for(int q=0;q<rowcount;q++)

{

for(int s=0;s<colcount;s++)

System.out.print(f[q][s]+"\t");

System.out.println();

}

}//display-------------------------------------------

void newcolcal()

{

System.out.println("Enter column name");

String tempstr=src.nextLine();

for(int q=0;q<colcount;q++)

if(f[0][q].equals(tempstr))

colvar=q;

}//newcolcal-----------------------------------------

void normal()

{

int flag=0;

for(int q=1;q<rowcount;q++)

{

newcol[flag]=Float.parseFloat(f[q][colvar]);

flag++;

}

                for(int q=0;q<newcol.length;q++)

                if(max<newcol[q])

                max=newcol[q];

                min=max;

                for(int q=0;q<newcol.length;q++)

                if(min>newcol[q])

                min=newcol[q];

for(int q=0;q<newcol.length;q++)

newcol[q]=(newcol[q]-min)/(max-min);

T=(int)Math.sqrt(rowcount-1);

}//normal---------------------------------------------

void display1()

{

for(int q=0;q<newcol.length;q++)

f[q+1][colvar]=Float.toString(newcol[q]);

display();

}//display1()-----------------------------------------

void distance()

{

dist=new double[rowcount-1];

System.out.println("Enter requirement:");

requirement=new float[colcount-2];

req=new String[colcount-2];

for(int q=0;q<req.length;q++)

req[q]=src.nextLine();

for(int q=0;q<req.length;q++)

{

if(req[q].equals("F"))

{req[q]="0";}

if(req[q].equals("M"))

{req[q]="1";}

}

for(int q=0;q<requirement.length;q++)

requirement[q]=Float.parseFloat(req[q]);

requirement[1]=(requirement[1]-min)/(max-min);

float colsum=0.0f;

for(int q=1;q<rowcount;q++)

{

                for(int s=1;s<colcount-1;s++)

                {

                float colminus=requirement[s-1]-Float.parseFloat(f[q][s]);

                float colsqr=colminus*colminus;

                colsum=colsum+colsqr;

                }

dist[q-1]=Math.sqrt(colsum);

//System.out.println(dist[q-1]);

colsum=0.0f;

}

set();

}//distance()-----------------------------

void set()

{

double[] Tset=new double[T];

int[] rowset=new int[T];

for(int q=0;q<Tset.length;q++)

{

Tset[q]=dist[q];

rowset[q]=q;

}

for(int q=T;q<dist.length;q++)

if(dist[q]<largest(Tset))

{

Tset[pos]=dist[q];

rowset[pos]=q;

}

commonclass(rowset);

}//set()--------------------------------------------

double largest(double[] arr)

{

pos=0;

double largest=0.0d;

for(int q=0;q<arr.length;q++)

if(arr[q]>largest)

{

largest=arr[q];

pos=q;

}

return(largest);

}//largest()------------------------------------------

void commonclass(int[] array)

{

String[] commonclass=new String[array.length];

String cl[]={"short","med","tall"};

intclcheck[]=new int[cl.length];

int common=0,clpos=0;

for(int q=0;q<clcheck.length;q++)

clcheck[q]=0;

for(int q=0;q<array.length;q++)

{

for(int s=0;s<colcount;s++)

System.out.print(f[array[q]+1][s]+"\t");

System.out.println();

}

for(int q=0;q<array.length;q++)

commonclass[q]=f[array[q]+1][colcount-1];

for(int q=0;q<commonclass.length;q++)

for(int s=0;s<cl.length;s++)

if(cl[s].equals(commonclass[q]))

clcheck[s]++;

for(int q=0;q<clcheck.length;q++)

if(common<clcheck[q])

{

common=clcheck[q];

clpos=q;

}

System.out.println("Most Common class is "+cl[clpos]);

}//commonclass()------------------------------------------

void read()

{

String file="person.txt";

String line=null;

try

{

BufferedReaderbr=new BufferedReader(new FileReader(file));

while((line=br.readLine())!=null)

rowcount++;

br.close();

br=new BufferedReader(new FileReader(file));

line=br.readLine();

colcount=line.split("\t").length;

br.close();

f=new String[rowcount][colcount];

newcol=new float[rowcount-1];

br=new BufferedReader(new FileReader(file));

int row=0,col=0,lc=0;

while((line=br.readLine())!=null)

{

line=line.replace('F','0');

line=line.replace('M','1');

String[] temp=line.split("\t");

                for(int q=0;q<temp.length;q++)

                f[row][q]=temp[q];

                row++;

}

br.close();

}

catch(FileNotFoundException ex)

{System.out.println("error");}

catch(IOException ex)

{System.out.println("error");}

}

public static void main(String arg[])

{

KNN knn=new KNN();

knn.read();

knn.newcolcal();

knn.normal();

knn.display1();

knn.distance();

}}