Frequency of numbers in txt file

Question

hi,
iam a newbie in java,just started learning it.
i have numbers (only from 1 to 5) input typically at run time the input breaks only if i enter -1. , these will be saved to a txt file,numbers.txt. now my problem is to count the frequency of numbers enterted in the txt file and ouput the result to another txt file(output.txt), i know the logic , but not completely sure how to implement it .
import java.io.File;
import java.util.Formatter;
import java.util.Scanner;
public class StudentPoll{
private Scanner x;
int[] frequency = new int[5];
int count =0;
public void openFile(){
try{
x = new Scanner(new File("numbers.txt"));
catch(Exception e){
System.out.printf("No File found");
public void readFile(){
while(x.hasNext()){
int a= x.nextInt();
switch(a){
case 1:
++frequency[0];
case 2:
++frequency[1];
case 3:
++frequency[2];
case 4:
++frequency[3];
case 5:
++frequency [4];
for(int rating =1; rating<=frequency.length;rating++){
System.out.printf("%s%10s\n","rating","Frequency");
System.out.printf("%6d%10d\n",rating,frequency[rating]);
public void closeFile(){
x.close();
and in the main method
StudentPoll read = new StudentPoll();
read.openFile();
read.readFile();
read.closeFile();
also, here i was just trying to get the output right on the console first, i don't how to write it to the txt file (output.txt)
and when i run this always the Frequency counter remains 1.
o/p when i run
run:
Enter integer result (1 - 5), -1 to quit: 1
Enter integer result (1 - 5), -1 to quit: 2
Enter integer result (1 - 5), -1 to quit: 1
Enter integer result (1 - 5), -1 to quit: 2
Enter integer result (1 - 5), -1 to quit: 3
Enter integer result (1 - 5), -1 to quit: 4
Enter integer result (1 - 5), -1 to quit: -1
rating Frequency
1 1
rating Frequency
2 1
rating Frequency
3 1
rating Frequency
4 1
rating Frequency
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
     at StudentPoll.readFile(StudentPoll.java:49)
     at CreateResults.main(CreateResults.java:84)
Java Result: 1
BUILD SUCCESSFUL (total time: 10 seconds)
Kindly somebody please help and guide me what was i doing wrong.
Edited by: 988824 on Feb 18, 2013 10:18 PM

Answer 1

here i have modified the code, but still getting the error in the count
import java.io.File;
import java.util.Formatter;
import java.util.Scanner;
public class StudentPoll_dasariHaritha {
private Scanner x;
int[] frequency = new int[5];
int count =0;
public void openFile(){
try{
x = new Scanner(new File("numbers.txt"));
catch(Exception e){
System.out.printf("No File found");
public void readFile(){
while(x.hasNext()){
int a= x.nextInt();
if(a==1){
frequency[0]=0;
++frequency[0];
break;
else if (a== 2){
frequency[1]=0;
++frequency[1];
break;
else if( a==3){
frequency[2]=0;
++frequency[2];
break;
else if (a==4){
frequency[3]=0;
++frequency[3];
break;
else if (a== 5){
frequency[4]=0;
++frequency [4];
break;
System.out.printf("%s%10s\n","Rating","Frequency");
System.out.printf("%s%10s\n","1",++frequency[0]);
System.out.printf("%s%10s\n","2",++frequency[1]);
System.out.printf("%s%10s\n","3",++frequency[2]);
System.out.printf("%s%10s\n","4",++frequency[3]);
System.out.printf("%s%10s\n","5",++frequency[4]);
public void closeFile(){
x.close();
in the main method iam calling these methods
StudentPoll_dasariHaritha read = new StudentPoll_dasariHaritha();
read.openFile();
read.readFile();
read.closeFile();
i think in the while loop iam making a mistake. can someone help me in rectifying it.