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C:\Program Files\Java\jdk1.6.0_24\bin>javac Question4Simulation.java
.\World.java:134: 'void' type not allowed here
if (grid[i][j] != null && grid[i][j].move()) {
^
1 error
Line 134...that part of the code was provided by the instructor, and I am lost here. Any help would be greatly appreciated.
/** World.java
* The World class stores data about the world by creating a
* WORLDSIZE by WORLDSIZE array of type Organism.
* Null indicates an empty spot, otherwise a valid object
* indicates an ant or doodlebug. To determine which,
* invoke the virtual function getType of Organism that should return
* ANT if the class is of type ant, and DOODLEBUG otherwise.
*/
public class World {
public static final int WORLDSIZE = 20;
/** 2-D Array of Organisms that make up a WORLDSIZE x WORLDSIZE
* grid. Some x,y positions may be null, some may contain Organisms
* of Ant or Doodlebug types.
*/
private Organism[][] grid;
/** Empty constructor.
* Initialize the grid to contain no organisms
*/
public World() {
grid = new Organism[WORLDSIZE][WORLDSIZE];
}
/** Returns the Organism stored in the grid array at x,y.
* @param x - X grid coordinate
* @param y - Y grid coordinate
* @return Organism - organism occupying this x,y coordinate of the
* grid, or NULL if no organism is at that location.
*/
public Organism getAt(int x, int y) {
if ((x >= 0) && (x < World.WORLDSIZE) &&
(y >= 0) && (y < World.WORLDSIZE)) {
return grid[x][y];
}
// return null for out of bounds checks
return null;
}
/** Puts the Organism on the grid at x,y.
* @param x - X grid coordinate
* @param y - Y grid coordinate
* @param org (Organism) - to place on the grid
*/
public void setAt(int x, int y, Organism org) {
if ((x >= 0) && (x < World.WORLDSIZE) &&
(y >= 0) && (y < World.WORLDSIZE)) {
grid[x][y] = org;
}
}
/** Displays the world grid in ASCII.text with Organisms denoted by
* their display character, getPrintableChar()
*/
public void displayWorld() {
System.out.println("\n\n*****************************************\n");
for (int i = 0; i < World.WORLDSIZE; i++) {
System.out.println();
for (int j = 0; j < World.WORLDSIZE; j++) {
if (grid[i][j]==null) {
System.out.print(".");
} else {
// X for Doodle, o for Ant
System.out.print(grid[i][j].getPrintableChar());
}
}
}
System.out.println();
}
/** This is the main routine that simulates one turn in the world.
* First, a flag for each organism is used to indicate if it has moved.
* This is because we iterate through the grid starting from the top
* looking for an organism to move. If one moves down, we don't want
* to move it again when we reach it.
* First move doodlebugs, then ants, and if they are still alive then
* we breed them. If any Organism is starving at the end of this turn,
* it will be killed off.
*/
public void SimulateOneStep() {
// For this new turn, reset all organisms to not moved
for (int i = 0; i < World.WORLDSIZE; i++) {
for (int j = 0; j < World.WORLDSIZE; j++) {
if (grid[i][j] != null) {
grid[i][j].setMoved(false);
}
}
}
// Move all Doodlebugs, checks that the Doodlebug found has not
// moved yet this turn (since it can move right and down to a
// new grid position
for (int i = 0; i < World.WORLDSIZE; i++) {
for (int j = 0; j < World.WORLDSIZE; j++) {
if ((grid[i][j] != null) &&
(grid[i][j] instanceof Doodlebug) &&
(!grid[i][j].getMoved()) ) {
// NOTE: setMoved() is used to track whether an Organism
// has "attempted" to move so it is not moved again,
// there is no other purpose for this variable
grid[i][j].setMoved(true);
}
}
}
// Move all Ants - similar to above Doodlebug move loop
for (int i = 0; i < World.WORLDSIZE; i++) {
for (int j = 0; j < World.WORLDSIZE; j++) {
if ((grid[i][j] != null) &&
(grid[i][j] instanceof Ant) &&
(!grid[i][j].getMoved()) ) {
// NOTE: setMoved() is used to track whether an Organism
// has "attempted" to move so it is not moved again,
// there is no other purpose for this variable
grid[i][j].setMoved(true);
}
}
}
// Kill off any starving Organisms
for (int i = 0; i < World.WORLDSIZE; i++) {
for (int j = 0; j < World.WORLDSIZE; j++) {
if (grid[i][j] != null)
grid[i][j].starve();
grid[i][j] = null;
}
}
// Breed any Organisms that have moved and have enough breedTicks
// to move.
for (int i = 0; i < World.WORLDSIZE; i++) {
for (int j = 0; j < World.WORLDSIZE; j++) {
if (grid[i][j] != null && grid[i][j].move()) {
grid[i][j].breed();
}
}
}
}
public boolean isAnt(int x, int y) {
boolean emptySpot = false;
if(grid[x][y] instanceof Ant)
emptySpot = true;
return emptySpot;
}
public boolean isNull(int x, int y) {
boolean emptySpot = false;
if(grid[x][y] == null)
emptySpot = true;
return emptySpot;
}
}
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