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Thread: first consul game in java (tic tace): problem with the winner check method

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    Default first consul game in java (tic tace): problem with the winner check method

    Hey,

    This is my first seruis code,
    I will be glad if you first help me solved the problem, and you are welcome to give me general tips

    When the "winner checker" func that I build is running the program is collapsing.

    https://pastebin.com/avdTkAC6
    xception in thread "main" java.lang.NullPointerException
    	at starting.Lerning_Arrays.winnerCheker(Lerning_Arrays.java:78)
    	at starting.Lerning_Arrays.main(Lerning_Arrays.java:32)
    Thanks Adam.

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    Super Moderator Norm's Avatar
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    Default Re: first consul game in java (tic tace): problem with the winner check method

    Exception in thread "main" java.lang.NullPointerException
    at starting.Lerning_Arrays.winnerCheker(Lerning_Array s.java:78)
    Look at the statement at line 78 and try to find the variable with the null value. Then backtrack in the code to see why that variable does not have a valid value.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: first consul game in java (tic tace): problem with the winner check method

    Quote Originally Posted by Norm View Post
    Look at the statement at line 78 and try to find the variable with the null value. Then backtrack in the code to see why that variable does not have a valid value.
    Hey,
    I have checked and I initialize the variable that was null this problem is solved/

    it's still doesn't find the winner the func is now working

    This is the problematic function:
    static String winnerCheker() {
    		String answer = "";
    		for(int a = 0 ; a < 8 ; a++) {
    			String line = "";
    			switch (a) {
    				case 0:
    					line = board[0][0] + board[0][1] + board[0][2];
    					break;
    				case 1:
    					line = board[1][0] + board[1][1] + board[1][2];
    					break;
    				case 2:
    					line = board[2][0] + board[2][1] + board[2][2];
    					break;
    				case 3:
    					line = board[0][0] + board[1][0] + board[2][0];
    					break;
    				case 4:
    					line = board[0][1] + board[1][1] + board[1][2];
    					break;
    				case 5:
    					line = board[1][2] + board[0][2] + board[2][2];
    					break;
    				case 6:
    					line = board[0][0] + board[1][1] + board[2][2];
    					break;
    				case 7:
    					line = board[0][2] + board[1][1] + board[2][0];
    					break;
    			}
    			if (line.equals("XXX")) {
    				answer = line;
    			} else if (line.equals("OOO")) {
    				answer = line;
    			}	
    		}
    		return answer;
    	}
    Last edited by Norm; May 20th, 2019 at 03:23 PM. Reason: Change Quote tag to code tag

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    Super Moderator Norm's Avatar
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    Default Re: first consul game in java (tic tace): problem with the winner check method

    What is the statement on line 78 where the exception happened?
    What variable on that line has the null value?
    What statement gave a value to that variable?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: first consul game in java (tic tace): problem with the winner check method

    Quote Originally Posted by Norm View Post
    What is the statement on line 78 where the exception happened?
    What variable on that line has the null value?
    What statement gave value to that variable?
    78: line = board[0][0] + board[0][1] + board[0][2];
    all variable as initialized

    static String line = "1"; //I initialized its with 1 just for its no to be null
    public static String[][] board; // this is the main array for the game
    	static String winnerCheker() {
    		for(int a = 0 ; a < 8 ; a++) {
    			switch (a) {
    				case 0:
    					line = board[0][0] + board[0][1] + board[0][2];
    					break;
    				case 1:
    					line = board[1][0] + board[1][1] + board[1][2];
    					break;
    				case 2:
    					line = board[2][0] + board[2][1] + board[2][2];
    					break;
    				case 3:
    					line = board[0][0] + board[1][0] + board[2][0];
    					break;
    				case 4:
    					line = board[0][1] + board[1][1] + board[1][2];
    					break;
    				case 5:
    					line = board[1][2] + board[0][2] + board[2][2];
    					break;
    				case 6:
    					line = board[0][0] + board[1][1] + board[2][2];
    					break;
    				case 7:
    					line = board[0][2] + board[1][1] + board[2][0];
    					break;
    			}
    			if (line.equals("XXX")) {
    				return line;
    			} else if (line.equals("OOO")) {
    				return line;
    			}	
    		}
    		return line;
    	}

    Thank you!!!
    Last edited by BlacKDay; May 21st, 2019 at 12:53 AM.

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    Super Moderator Norm's Avatar
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    Default Re: first consul game in java (tic tace): problem with the winner check method

    Sorry, I still do not understand what variable has the null value.
    Can you give the name of the variable with the null value?

    If you can not tell which variable has the null value, add a print statement just before line 78 that prints the values of the variables on line 78.

    78: line = board[0][0] + board[0][1] + board[0][2];
    What values are in board[0][0] and board[0][1] and board[0][2]?

    Where is the variable: board assigned a value?
    If you don't understand my answer, don't ignore it, ask a question.

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