如何从递归方法返回布尔值？

Question

This method finds a path from top left to bottom right in a given labyrinth. I have checked and my method finds me a path but i cant get it to return true when its done. It prints out "You made it" from my if-statement, but it dosent returns true.

if((x0 == x1) && (y0 == y1)) {
        System.out.println(l);
        System.out.println("You made it");
        return true;
    }

I know it's something with recursive and that you return values in a diffrent way. I still dont have a clue how to return my value correctly.

Heres the method:

public static boolean findPath(int x0, int y0, int x1, int y1, Labyrinth l) {
    l.setMark(x0, y0, true);
    if((x0 == x1) && (y0 == y1)) {
        System.out.println(l);
        System.out.println("You made it");
        return true;
    }
    //is it possible to move in any new direction? if yes, then move
    if(l.canMove(Labyrinth.Direction.RIGHT, x0, y0) && !l.getMark(x0+1, y0) && !hasBeen[x0+1][y0]){
        findPath(x0+1, y0, x1, y1, l);
    }else if(l.canMove(Labyrinth.Direction.DOWN, x0, y0) && !l.getMark(x0, y0+1)&& !hasBeen[x0][y0+1]){;
        findPath(x0, y0+1, x1, y1, l);
    }else if(l.canMove(Labyrinth.Direction.UP, x0, y0) && !l.getMark(x0, y0-1)&& !hasBeen[x0][y0-1]){
        findPath(x0, y0-1, x1, y1, l);
    }else if(l.canMove(Labyrinth.Direction.LEFT, x0, y0) && !l.getMark(x0-1,y0)&& !hasBeen[x0-1][y0]){
        findPath(x0-1, y0, x1, y1, l);
    }else{
        //go back one step and set hasBeen true for this coordinate
        l.setMark(x0,y0,false);
        hasBeen[x0][y0]=true;
        if(l.getMark(x0+1, y0)){
            findPath(x0+1, y0, x1, y1, l);
        }else if(l.getMark(x0, y0+1)){
            findPath(x0, y0+1, x1, y1, l);
        }else if(l.getMark(x0, y0-1)){
            findPath(x0, y0-1, x1, y1, l);
        }else if(l.getMark(x0-1,y0)){
            findPath(x0-1, y0, x1, y1, l);
        }
    }
    return false;
}

}

Answer 1

You need to propagate the return statements. Instead of just calling findPath(x0+1, y0, x1, y1, l); recursively, you need to do:

return findPath(x0+1, y0, x1, y1, l);

Also, with that, you can do away with all the 'else' statements. Just the if's will suffice.