java - StackOverflowError during recursive calls to find closest empty index in 2D array -
i trying use recursive approach figure out closest empty element in 2d array if input index has element. example, call method tryplant(int x, int y) put symbol in 2d (32x32) array:
- ecoarray[x][y] == "." (empty) fill "~"
- if there element besides ".", recursively find next empty spot in same row first, column.
the code method is:
public void tryplant(int x, int y){ if (this.ecoarray[x][y] == ".") { this.ecoarray[x][y] = "~"; }else{ if((y - 1) >= 0) { tryplant(x, y - 1); } else if((y + 1) <= 32){ tryplant(x, y + 1); }else if((x - 1) >= 0 ) { tryplant(x - 1, y); }else if((x + 1) <= 32){ tryplant(x + 1, y); } } } i calling method in class this:
plant p1; private void initplants(){ int size = p1.initpop; (int = 0; < size; i++) { int randx = randgen(); int randy = randgen(); plant plant = new plant(randx, randy, this.ecoarray); } } the randgen() method returns random integer between 0-31.
sometimes random generator gives me indexes such not collide other objects. example of (the | obstacles):
i want know why stackoverflow error , can fix it. if need other portions of code, please ask. pretty new java.
edit
public static int left = 0; public static int right = 0; public void tryplant(int x, int y){ if (this.ecoarray[x][y] == ".") { this.ecoarray[x][y] = "~"; }else{ if((y - 1) >= 0) { this.left++; tryplant(x, y - 1); } else if((y + this.left + 1) <= 32){ tryplant(x, y + this.left + 1); this.left = 0; }else if((x - 1) >= 0 ) { this.right++; tryplant(x - 1, y); }else if((x + this.right + 1) <= 32){ tryplant(x + + this.right + 1, y); this.right = 0; } } }
approximately happens is: each time function called stored in memory stack. when function return, stored cleared. but, if call many functions, fullfil memory , stackoverflow error sent.
you stackoverflow error because somewhere have loop in algorithm. cause many call tryplant().
- first, when find way pass, return. (where
char == '~') - second, there obstacle, return. (where
char == '|') third, don't try directions:
if ((y - 1) >= 0) { this.left++; tryplant(x, y - 1); } else if ((y + this.left + 1) <= 32){ tryplant(x, y + this.left + 1); this.left = 0; } else if ((x - 1) >= 0 ) { this.right++; tryplant(x - 1, y); } else if ((x + this.right + 1) <= 32){ tryplant(x + + this.right + 1, y); this.right = 0; }
i tried , seems work:
public class test { private char[][] ecoarray; public test() { string[] stringarray = new string[] { "||.|.||..|..||.|.||||||||..||.||", "||||....||..|||..||....|.||..|||", "||||||...|.|||...||.|..||..||||.", "||...||.|.|||.||||.|||||.|...||.", "|.|....|.|||||||||..||.|.|.||...", "..|||.||||...|..||.||..|..||||.|", "..|.||||||..||.||||..|||.|.|...|", "|||||.||.|||...||...||..||.|||..", "||||.|..||||||..|.|||...||.||.|.", "|||.|||||.|||||.||||.|....||||||", "||...||||||.|.|||||||||||.|.|.||", "|.|.||||||||.||||....|.||||.||||", "||..||.||||.|..||.|||..||.|.||||", "..||..|..||.|.|||..|||..|||||.|.", "||||.|.||.||||.|||||..|||.|.....", "..|.|.|||..|||..||.||||.|||.|..|", "||||.|..|||||||.|||||.||.|.|....", "..|...||...|||||.|...|..|...|||.", "..|||||||..||...||||||..|..|||||", "||||..||.|.|||||.||||.|||||.||..", "|||||.||||.|....||||....||.||...", "||..||.|||||.||||||..||..|....||", "|.||||.||..|...|.|..|||.|.|||.||", "...||||.|..|||.|||..|.||...|.|||", ".||||.|..|.|..||..||..||..||||||", "|||.|||..|||..||||.||||.|.||.|||", "|||||.||...|.|.|.||...|||..|.|||", ".||||.|.|.|||...|||.|||.....||||", "|||.|||.|.|...||.|....||||.|.|||", ".||||||.|||||||...||..|||.||||.|", "||||.|||||.|.||.||||..|.|||.||||", "|.|.||||....|.||||||||.|||||.|.|" }; this.ecoarray = new char[32][32]; int index = 0; (string s : stringarray) { this.ecoarray[index] = s.tochararray(); ++index; } } public void tryplant(int x, int y){ if (this.ecoarray[x][y] == '~' || this.ecoarray[x][y] == '|') { return; } if (this.ecoarray[x][y] == '.') { this.ecoarray[x][y] = '~'; if ((y - 1) >= 0) { tryplant(x, y - 1); } if((y + 1) < 32){ tryplant(x, y + 1); } if((x - 1) >= 0 ) { tryplant(x - 1, y); } if((x + 1) < 32){ tryplant(x + 1, y); } } } private void displayinconsole() { (char[] cl : this.ecoarray) { system.out.println(cl); } } public static void main(string[] args) { (int x = 0; x < 32; x++) { (int y = 0; y < 32; y++) { test t = new test(); t.tryplant(x, y); system.out.println("after tryplant('" + x + "','" + y + "'): "); t.displayinconsole(); } } } } is doing need ? don't understand want start , want stop...
the result big sorry...
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