Thread: 1 MINOR ERROR IN PROGRAM

Hi,
here is my program:

package practice;
 
import java.util.*;
public class New2 {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String [] words= {"write", "that", "program", "fusion"};
 
		Scanner in= new Scanner(System.in);
		char newGame;
 
		{
		int index= (int)(Math.random() * words.length);
 
		String word= words[index];
		StringBuilder guess= new StringBuilder();
 
		for (int i=0; i < word.length(); i++){
			guess.append('*');
		}
		int CorrectGuesses=0;
		int Misses=0;
 
		while (CorrectGuesses < word.length()){
			System.out.println("(Guess) Enter a letter in word " +guess+ " > ");
			String s= in.nextLine();
			char letter= s.charAt(0);
 
		if (guess.indexOf(letter) >= 0){
			System.out.println("\t" +letter+ " is already in the word");}
		else if (word.indexOf(letter) < 0) {
			System.out.println("\t" +letter+ " is not in the word");
			Misses++;}
		else {
			int h= word.indexOf(letter);
			while (h >= 0) {
				guess.setCharAt(h, letter);
				CorrectGuesses++;
				h= word.indexOf(letter, h+1);
 
				}		
			}
		}
		System.out.println("The word is " +word+ ". You missed " +Misses+ " time(s).");
 
		System.out.println("Do you want to guess another word? Enter y or n>");	
	}
 
	}
}

I have one error: the line >> if (guess.indexOf(letter) >= 0){
This line is preventing my program from running

The error: The method indexOf(String) in the type StringBuilder is not applicable for the arguements (char).

because you are passing an argument/parameter of type char, as StringBuilder (Java Platform SE 7 ) says, indexOf method accepts a String object, not a char primitive type.
you better parse/convert your letter of type char into String object.
please:
String (Java Platform SE 7 ) or
Character (Java Platform SE 7 )
to know how to convert char to String.

2. I have one error: the line >>Scanner in= new Scanner(new FileReader("list.txt"));

The error: syntax error on token ";" , PrimitiveType expected after this token

actually you a got a syntax error there. look at this code of yours:
String [] words= new String [1000];
Scanner in= new Scanner(new FileReader("list.txt"));
[] words= in.nextLine();
look at the last line of your codes, that is invalid syntax, if you want to put a value in specified element of your array, brackets should be after the variable name and it must contain an index.
example:

words[0] = "Java Girl";
that statement declares first element of String array words is "Java Girl".

1. I have one error: the line >> if (guess.indexOf(letter) >= 0){
This line is preventing my program from running

The error: The method indexOf(String) in the type StringBuilder is not applicable for the arguements (char)

Please read my above reply, (#2)

look at this part of your code
String words [1000]= new String " ";
that is an invalid declaration of array as what Arrays (The Java™ Tutorials > Learning the Java Language > Language Basics) says,
it should be like this:
String[] myArray = new String[desired length] or
String myArray[] = new String[desired length]
NOT
String words [1000]= new String " "; that is an invalid syntax for declaration of array.

Same run time error exists even after the correct format but thanks

oh,, ArrayIndexOutOfBoundsException means that you attempted to access an element whose index is beyond the size.
Index in array always starts with 0, and usually ends with the length - 1.

so if the length of your array is 10, accessing element 10 would throw ArrayIndexOutOfBounds Exception. because the last element lies at index 9.
Element Array Index
First array[0]
Second array[1]
Third array[3]
.
.
.
Tenth array[9]

This is how the file i am attempting to read from is layout:
Umbrella
Rain
Jacket
Boots
Geography
Pizza
Music
Disco
Roti
Optician
Violin


Any string is suppose to be selected from it

did you read it successfully? what is the problem now?

Well, I am still getting the ArrayIndexOutOfBoundsException error so I am unable to run it successfully.
Here is my current program:

package practice;
 
import java.util.*;
import java.io.*;
 
public class New2 {
	public static void main(String[] args) throws IOException{
		//String [] words= new String [1000];
		String words []= new String [20];
		Scanner in= new Scanner(new FileReader("list.txt"));
		words [] = in.nextLine();
 
		{
		int index= (int)(Math.random() * words.length);
 
		String word= words[index];
		StringBuilder guess= new StringBuilder();
 
		for (int i=0; i < word.length(); i++){
			guess.append('*');
		}
		int CorrectGuesses=0;
		int Misses=0;
 
		while (CorrectGuesses < word.length()){
			System.out.println("(Guess) Enter a letter in word " +guess+ " > ");
			String s= in.nextLine();
			char letter= s.charAt(0);
 
		//if (guess.indexOf(letter) >= 0){
			//System.out.println("\t" +letter+ " is already in the word");}
		if (word.indexOf(letter) < 0) {
			System.out.println("\t" +letter+ " is not in the word");
			Misses++;}
		else {
			int h= word.indexOf(letter);
			while (h >= 0) {
				guess.setCharAt(h, letter);
				CorrectGuesses++;
				h= word.indexOf(letter, h+1);
 
				}		
			}
		}
		System.out.println("The word is " +word+ ". You missed " +Misses+ " time(s).");
 
		System.out.println("Do you want to guess another word? Enter y or n>");	
	}
    in.close();
	}
}

at what part/line do get it? I'm sure it is saying a line number on which you got an error.
is that really the error? because this line words [] = in.nextLine(); will make you have compilation error?

yes,words [] = in.nextLine(); is causing the compilation error

because that is invalid syntax, that statement is attempting to put a value in specified index of array, but you did not provide any index on it.
words[0] = in.nextLine(); 0 inside the bracket is the index of array where I want to put the return value of in.nextLine();
in short, you should an integer inside that bracket that is greater than and not equal to the size of your array.

or, well I fixed that but the error is now:
Exception in thread "main" java.lang.NullPointerException
at practice.New2.main(New2.java:19)

Can you paste your updated code here?
can you paste also the line 19 of your code? thanks.

package practice;
 
import java.util.*;
import java.io.*;
 
public class New2 {
	public static void main(String[] args) throws IOException{
 
		String words []= new String [20];
		Scanner in= new Scanner(new FileReader("list.txt"));
		words [0] = in.nextLine();
 
		{
		int index= (int)(Math.random() * words.length);
 
		String word= words[index];
		StringBuilder guess= new StringBuilder();
 
		for (int i=0; i < word.length(); i++){
			guess.append('*');
		}
		int CorrectGuesses=0;
		int Misses=0;
 
		while (CorrectGuesses < word.length()){
			System.out.println("(Guess) Enter a letter in word " +guess+ " > ");
			String s= in.nextLine();
			char letter= s.charAt(0);
 
		//if (guess.indexOf(letter) >= 0){
			//System.out.println("\t" +letter+ " is already in the word");}
		if (word.indexOf(letter) < 0) {
			System.out.println("\t" +letter+ " is not in the word");
			Misses++;}
		else {
			int h= word.indexOf(letter);
			while (h >= 0) {
				guess.setCharAt(h, letter);
				CorrectGuesses++;
				h= word.indexOf(letter, h+1);
 
				}		
			}
		}
		System.out.println("The word is " +word+ ". You missed " +Misses+ " time(s).");
 
		System.out.println("Do you want to guess another word? Enter y or n>");	
	}
    in.close();
	}
}

line 19: for (int i=0; i < word.length(); i++){

Oh I get it now. Here is what happened at back of your code:
you declared a String array whose length is 20,
so by default, all elements of your array is null (a null pointer).
next you wrote something in first element of your array, words[0] = in.nextLine(); so first element of your String array has a String value, and the rest is null.
next you generated a random integer and make it as the index.
and you declared word = words[index];
if the value of index is not 0 (since it is randomly generated), you put a null pointer in String word.
Something like this String word = null;
did you get it? because all (except for first element) element of your array is null.

I think you better put a String value on each element of your array first.

ok so how do i go about putting a String value on each element of the array ?

I think you assumed that you have 20 words in your file (separated by carriage return/enter).
so read each line and store it in every element of your array.
words[0] = first word of file.
words[1] = second word of file
words[19] = last word of file