need help with "turtle" problem

[cbear315]

I am doing an assignment and am brand new to java. I just need to know where in this coding I can tweak the 1's to display as * and the 0's to disappear when option 6 is chosen. Any help would be great! Thanks.


//DrawingTurtle.java
//Allows user to draw on a 20 x 20 grid by command

import java.util.Scanner;

public class DrawingTurtle {
private static short direction = 0;
private static boolean penDown;
private static int turtleX = 0, turtleY = 0; //initializes the turtle to 0,0
private static int[][] grid = new int[20][20]; //grid is 20 x 20

public static void main(String[] args) {
initGrid(grid);
Scanner in = new Scanner(System.in);
printMenu(); //calls for function to display options
int nextCommand = in.nextInt();
while (nextCommand != 9) {
switch (nextCommand) {
//option for pen down
case 1:
penDown = false;
break;
//option for pen up
case 2:
penDown = true;
break;
//option to turn right
case 3:
direction++;
break;
//option to turn right
case 4:
direction--;
break;
//asks the user when 5 is entered to obtain number of steps
case 5:
System.out.println("How many spaces?");
int move = in.nextInt();
if (move <= 20)
while (--move != 0)
turtleMove();
break;
//displays the grid
case 6:
printArray();
break;
default:
System.err.println("Please enter valid command:\n");
break;
}
turtleMove();
System.out.println("Next command: ");
nextCommand = in.nextInt();
}
}

//shows the user what the options are the entire time the program is running
private static void printMenu() {
System.out.println("Commands List:"
+ "\n\n\t1 Pen up\n"
+ "\t2 Pen down\n"
+ "\t3 Turn right\n"
+ "\t4 Turn left\n"
+ "\t5 Move forward an inputted number\n"
+ "\t6 Display the 20 x 20 array\n"
+ "\t9 End of data (sentinel)\n"
+ "Please enter a command number: ");
}

//keeps track of the turtle on the grid
private static void initGrid(int[][] grid) {
for (int i = 0; i < grid.length; i++) {
for (int j = 0; j < grid[i].length; j++) {
grid[i][j] = 0;
}
}
}

//moves the turtle in a direction that is inputted
private static void turtleMove() {
switch (direction) {
case 0:
turtleX++;
break;
case 1:
turtleY++;
break;
case 2:
turtleX--;
break;
case 3:
turtleY--;
break;
default:
if (direction < 0)
direction = 3;
else
direction = 4;
turtleMove();
break;
}
if (penDown) {
if (turtleX < 20 && turtleY < 20)
grid[turtleX][turtleY] = 1; /*applies a 1 to the spot
/*if the pen is down*/
else {
direction = 0;
turtleMove();
}
}
}

//displays the grid as the user has made it so far
private static void printArray() {
for (int i = 0; i < grid.length; i++) {
for (int j = 0; j < grid[i].length; j++) {
System.out.print(grid[i][j]);
System.out.print(" ");
}
System.out.println();
}
}
}

[masijade]

This spot needs to change

System.out.print(grid[i][j]);

[cbear315]

it needs to change to what? can i just plug in " * " for i and " " for b?

[masijade]

You want a space for zero and * for one right? So add an if statement to look at the value and then print the proper value, of course.

[Singing Boyo]

Put an if statement in checking if the option is selected, if it is, use this line as the print statement, and dont use the other one (put in an else block). The code assumes only 1 and 0 are in the array, otherwise you will need additional if-else statements.

System.out.print(grid[i][j]==0?' ':'*');