CODEWITHSUNDEEP
javachess
user3816650
user3816650

Reputation: 31

Need help preventing Pawn piece from moving two square after first move

i am developing a chessgame and have been able to made my Pawn piece move both one and two squares forward but i am having difficulty preventing it from moving two squares forward after its first move. Please i will be grateful if someone can help me with a logic or idea on how to implement it.

Here is my code:

 private boolean isValidPawnMove(int sourceRow, int sourceColumn, int targetRow, int        
 targetColumn) {

    boolean isValid = false;

    if(isTargetLocationFree()){ 
        if(sourceColumn == targetColumn){
            //same column
            if(sourcePiece.getColor() == Piece.YELLOW_COLOR){
                //yellow
                if(sourceRow + 1 == targetRow ){
                    //move one up
                    isValid = true;

                }else if(sourceRow + 2 == targetRow ){
                    isValid = true;
                }else{
                    //not moving one up
                    isValid = false;
                }                               
            }else{
                //brown
                if(sourceRow - 1 == targetRow){
                    //move one down
                    isValid = true;
                }else if(sourceRow - 2 == targetRow){
                    isValid = true;

                }else{
                    //not moving one down
                    isValid = false;
                }                   
            }
        }else{
            //not the same column
            isValid = false;
        }
    }else if(isTargetLocationCaptureable()){
        if(sourceColumn + 1 == targetColumn || sourceColumn - 1 == targetColumn ){
            //one column to the right or left
            if(sourcePiece.getColor() == Piece.YELLOW_COLOR){
                //yellow
                if(sourceRow + 1 == targetRow){
                    //move one up
                    isValid = true;
                }else{
                    //not moving one up
                    isValid = false;
                }
            }else{
                //brown
                if(sourceRow - 1 == targetRow ){
                    //move one down
                    isValid = true;
                }else{
                    //not moving one down                       
                    isValid = false;
                }
            }
        }else{
            //One column to the left or right
            isValid = false;
        }   
    }       
    return isValid;
}

private boolean isTargetLocationCaptureable(){
    if(targetPiece == null){
        return false;
    }else if( targetPiece.getColor() != sourcePiece.getColor()){
        return true;
    }else{
        return false;
    }
}

private boolean isTargetLocationFree(){
    return targetPiece == null;
}

Upvotes: 0

Views: 400

Answers (4)

Ted Hopp
Ted Hopp

Reputation: 234797

For yellow pieces, just check that sourceRow is 1 (or 2, depending on how you are numbering rows):

    ...
}else if(sourceRow == 1 && targetRow == 3){
    // double-row first move
    isValid = true;
}else{
    ...

Do a similar thing for the brown pieces.

Upvotes: 2

Michael Barz
Michael Barz

Reputation: 276

I'd do it one of two ways:

  • Check if the pawn is in the row it starts in. If it is, allow 2-space moves, otherwise, don't.
  • Give each pawn a boolean that is false if it hasn't been moved, and true if it has, than check that. (Wouldn't recommend this as it doesn't seem you're making Pawn an object so it'd be very difficult to implement)

Upvotes: 0

Adam Yost
Adam Yost

Reputation: 3625

Assuming you have a class for your Pawn, then you should create a field in the class called firstmove or numMoves. This would be set to true or 0 respectively, and after the first move set to false or numMoves++. Then, in your validity checker, you can say 

if p.firstMove
    //accept 1 or 2
else
    //accept only 1

Upvotes: 0

Eran
Eran

Reputation: 393841

I won't write the code for you, but your condition should be based on the sourceRow. If your source row is the original row the pawn started on (second or seventh row, depending on which player), only then can the pawn move two rows.

Upvotes: 5

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