Decision Tree Algorithm:(Classification Problem Java Code)

Java Program for Decision Tree Algorithm.

import java.util.*; //Aim: To implement Decision Tree algorithm in java class tree { public double hd; public double p; char ch; String parent; tree(char c,int x) { ch=c; if(x==1) parent="outlook"; else if(x==2) parent="temperature"; else if(x==3) parent="humidity"; else if(x==4) parent="windy"; } } class d_tree { static char outlook[]={'S','S','O','R','R','R','O','S','S','R','S','O','O','R'}; static char temperature[]={'B','B','B','M','C','C','C','M','C','M','M','M','B','M'}; static char humidity[]={'H','H','H','H','N','N','N','H','N','N','N','H','N','H'}; static char windy[]={'F','T','F','F','F','T','T','F','F','F','T','T','F','T'}; static char class1[]={'N','N','P','P','P','N','P','N','P','P','P','P','P','N'}; static double G1,G2,G3,G4; static double HD; static double play=9.0/14.0; static double nplay=5.0/14.0; static double temp1,temp2; static int row=0,column=0; static char classify[][]=new char[10][10]; static tree cal_hd(tree t,int choice) { double count1=0,count2=0; if(choice==1) {for(int i=0;i<14;++i) {if(t.ch==outlook[i] && class1[i]=='P') ++count1; else if(t.ch==outlook[i] && class1[i]=='N') ++count2; }} if(choice==2) {for(int i=0;i<14;++i) {if(t.ch==temperature[i] && class1[i]=='P') ++count1; else if(t.ch==temperature[i] && class1[i]=='N') ++count2; }} if(choice==3) {for(int i=0;i<14;++i) {if(t.ch==humidity[i] && class1[i]=='P') ++count1; else if(t.ch==humidity[i] && class1[i]=='N') ++count2; }} if(choice==4) {for(int i=0;i<14;++i) {if(t.ch==windy[i] && class1[i]=='P') ++count1; else if(t.ch==windy[i] && class1[i]=='N') ++count2; }} temp1=count1/(count1+count2); temp2=count2/(count1+count2); t.p=(count1+count2)/14; if(temp1==0 || temp2==0) t.hd=0; else t.hd=temp1*(Math.log(1/temp1)/Math.log(10))+temp2*(Math.log(1/temp2)/Math.log(10)); return t; } static int check_if_equal(char ca[][],int cnt) { int count1=0,count2=0,count3=0; char c1=ca[0][0],c2=ca[0][1],c3=ca[0][2]; for(int i=0;i<cnt;++i) { if(ca[i][0]==c1) ++count1; if(ca[i][1]==c2) ++count2; if(ca[i][2]==c3) ++count3; } if(count1==cnt) return 0; else if(count2==cnt) return 1; else if(count3==cnt) return 2; else return -1; } static void compute(char ch) { char ca1[][]=new char[10][10]; char ca2[][]=new char[10][10]; char ca3[][]=new char[10][10]; int cnt1=0; int cnt2=0; for(int i=0;i<14;++i) { if(outlook[i]==ch) { ca1[cnt1][0]=temperature[i]; ca1[cnt1][1]=humidity[i]; ca1[cnt1][2]=windy[i]; ca1[cnt1][3]=class1[i]; ++cnt1; } } int check1=0,check2=0; for(int i=0;i<cnt1;++i) { if(ca1[i][3]=='P') ++check1; else if(ca1[i][3]=='N') ++check2; if(check1==cnt1) { classify[row][column++]=ch; classify[row][column++]='P'; System.out.print("--------->PLAY"); return; } else if(check2==cnt1) { classify[row][column++]=ch; classify[row][column++]='N'; System.out.print("--------->NO PLAY"); return; } } //end of for loop /*System.out.println("The array containing outlook value ch"); for(int i=0;i<9;++i) { for(int j=0;j<9;++j) { System.out.print(" "+ca1[i][j]); } System.out.println(); } */ //The array containing outlook value ch and class1=P cnt1=0; for(int i=0;i<10;++i) { if(ca1[i][3]=='P') { ca2[cnt1][0]=ca1[i][0]; ca2[cnt1][1]=ca1[i][1]; ca2[cnt1][2]=ca1[i][2]; ca2[cnt1][3]=ca1[i][3]; ++cnt1; } } classify[row][column++]=ch; int z=check_if_equal(ca2,cnt1); //System.out.println("The value of Z is "+z); if(z==0) { System.out.print("\n--------->TEMPERATURE("+ca2[0][0]+")--------->PLAY\n"); classify[row][column++]=ca2[0][0]; classify[row][column++]='P'; } else if(z==1) { System.out.print("\n--------->HUMIDITY("+ca2[0][1]+")--------->PLAY\n"); classify[row][column++]=ca2[0][1]; classify[row][column++]='P'; } else if(z==2) { System.out.print("\n--------->WINDY("+ca2[0][2]+")--------->PLAY\n"); classify[row][column++]=ca2[0][2]; classify[row][column++]='P'; } /* System.out.println("The array containing ch and play"); for(int i=0;i<9;++i) { for(int j=0;j<9;++j) { System.out.print(" "+ca2[i][j]); } System.out.println(); } */ //The array containing outlook value ch and class1=N cnt1=0; for(int i=0;i<10;++i) { if(ca1[i][3]=='N') { ca3[cnt1][0]=ca1[i][0]; ca3[cnt1][1]=ca1[i][1]; ca3[cnt1][2]=ca1[i][2]; ca3[cnt1][3]=ca1[i][3]; ++cnt1; }} ++row; column=0; classify[row][column++]=ch; z=check_if_equal(ca3,cnt1); if(z==0) { System.out.print("--------->TEMPERATURE("+ca3[0][0]+")--------->NO PLAY"); classify[row][column++]=ca3[0][0]; classify[row][column++]='N'; } else if(z==1) { System.out.print("--------->HUMIDITY("+ca3[0][1]+")--------->NO PLAY"); classify[row][column++]=ca3[0][1]; classify[row][column++]='N'; } else if(z==2) { System.out.print("--------->WINDY("+ca3[0][2]+")--------->NO PLAY"); classify[row][column++]=ca3[0][2]; classify[row][column++]='N'; } /*System.out.println("The array containing ch and not play"); for(int i=0;i<9;++i) { for(int j=0;j<9;++j) { System.out.print(" "+ca3[i][j]); } System.out.println(); } */ } public static void main(String args[]) { Scanner scr=new Scanner(System.in); HD=play*(Math.log(1/play)/Math.log(10))+nplay*(Math.log(1/nplay)/Math.log(10)); System.out.println("\nThe value of H(D) is "+HD); tree sunny=new tree('S',1); tree overcast=new tree('O',1); tree rain=new tree('R',1); tree hot=new tree('B',2); tree mild=new tree('M',2); tree cool=new tree('C',2); tree high=new tree('H',3); tree normal=new tree('N',3); tree tru=new tree('T',4); tree fal=new tree('F',4); sunny=cal_hd(sunny,1); overcast=cal_hd(overcast,1); rain=cal_hd(rain,1); hot=cal_hd(hot,2); mild=cal_hd(mild,2); cool=cal_hd(cool,2); high=cal_hd(high,3); normal=cal_hd(normal,3); tru=cal_hd(tru,4); fal=cal_hd(fal,4); G1=HD-(sunny.p*sunny.hd+overcast.p*overcast.hd+rain.p*rain.hd); G2=HD-(hot.p*hot.hd+mild.p*mild.hd+cool.p*cool.hd); G3=HD-(high.p*high.hd+normal.p*normal.hd); G4=HD-(tru.p*tru.hd+fal.p*fal.hd); int gflag=0; System.out.println("\nGain(D,Outlook)= "+G1 +"\nGain(D,Temperature)= "+G2+"\nGain(D,Humidity)= "+G3+"\nGain(D,Windy)= "+G4); System.out.print("\nThe Splitting factor is "); if(G1>G2 && G1>G3 && G1>G4) System.out.println("Outlook"); else if(G2>G1 && G2>G3 && G2>G4) System.out.println("Temperature"); else if(G3>G2 && G3>G1 && G3>G4) System.out.println("Humidity"); else if(G4>G2 && G4>G3 && G4>G1) System.out.println("Windy"); System.out.println("\nThe Tree is as follows:-"); System.out.print("\nOUTLOOK(S)"); compute('S'); ++row; column=0; System.out.print("\n\n\nOUTLOOK(O)"); compute('O'); ++row; column=0; System.out.print("\n\n\nOUTLOOK(R)"); compute('R'); char input[]=new char[4]; String s; System.out.println("\nMenu:\n\nOutlook: Sunny=S Overcast=O Rainy=R\n\nTemperature: Hot=B Medium=M Cool=C\n\nHumidity: High=H Normal=N\n\nWindy: True=T False=F"); System.out.println("\n\nEnter your new tuple to be classified "); System.out.print("\nOutlook(S/O/R)= "); s=scr.nextLine(); input[0]=s.charAt(0); System.out.print("\nTemperature(B/M/C)= "); s=scr.nextLine(); input[1]=s.charAt(0); System.out.print("\nHumidity(H/N)= "); s=scr.nextLine(); input[2]=s.charAt(0); System.out.print("\nWindy(T/F)= "); s=scr.nextLine(); input[3]=s.charAt(0); /* Display classify for(int i=0;i<9;++i) { for(int j=0;j<9;++j) { System.out.print(" "+classify[i][j]); } System.out.println(); } */ System.out.print("Your input is "); for(int i=0;i<4;++i) System.out.print(" "+input[i]); int inc1=0; do { if(input[0]==classify[inc1][0]) { if(classify[inc1][1]=='P') { System.out.println("\n\nTuple classified as PLAY"); break; } else if(input[1]==classify[inc1][1] || input[2]==classify[inc1][1] || input[3]==classify[inc1][1]) { if(classify[inc1][2]=='P') { System.out.println("\n\nTuple classified as PLAY"); break; } else if(classify[inc1][2]=='N') { System.out.println("\n\nTuple classified as NO PLAY"); break; } } } ++inc1; } while(true); } } /*OUTPUT1 C:\Users\Aditya\Desktop\aditya>java d_tree The value of H(D) is 0.2830542780615224 Gain(D,Outlook)= 0.07427909717678749 Gain(D,Temperature)= 0.00879686881360553 Gain(D,Humidity)= 0.04570704031674405 Gain(D,Windy)= 0.014487679755121663 The Splitting factor is Outlook The Tree is as follows:- OUTLOOK(S) --------->HUMIDITY(N)--------->PLAY --------->HUMIDITY(H)--------->NO PLAY OUTLOOK(O)--------->PLAY OUTLOOK(R) --------->WINDY(F)--------->PLAY --------->WINDY(T)--------->NO PLAY Menu: Outlook: Sunny=S Overcast=O Rainy=R Temperature: Hot=B Medium=M Cool=C Humidity: High=H Normal=N Windy: True=T False=F Enter your new tuple to be classified Outlook(S/O/R)= S Temperature(B/M/C)= M Humidity(H/N)= N Windy(T/F)= T Your input is S M N T Tuple classified as PLAY ------------------------------------------------------------------------ OUTPUT2 C:\Users\Aditya\Desktop\aditya>java d_tree The value of H(D) is 0.2830542780615224 Gain(D,Outlook)= 0.07427909717678749 Gain(D,Temperature)= 0.00879686881360553 Gain(D,Humidity)= 0.04570704031674405 Gain(D,Windy)= 0.014487679755121663 The Splitting factor is Outlook The Tree is as follows:- OUTLOOK(S) --------->HUMIDITY(N)--------->PLAY --------->HUMIDITY(H)--------->NO PLAY OUTLOOK(O)--------->PLAY OUTLOOK(R) --------->WINDY(F)--------->PLAY --------->WINDY(T)--------->NO PLAY Menu: Outlook: Sunny=S Overcast=O Rainy=R Temperature: Hot=B Medium=M Cool=C Humidity: High=H Normal=N Windy: True=T False=F Enter your new tuple to be classified Outlook(S/O/R)= S Temperature(B/M/C)= M Humidity(H/N)= H Windy(T/F)= T Your input is S M H T Tuple classified as NO PLAY */

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