Java version:
public class RandomWalk
{
public static void main(String[] args)
{
int[] coor = new int[2]; //this houses the (x,y) coordinate
coor[0] = coor[1] = 1; //begin at (1,1)
int move = 0;
final int size = 10; //this creates 10x10 grid
while(!(coor[0]==size && coor[1]==size)) //game continues while not at the extreme corner
{
boolean valid = false; //indicates whether or not a valid location has been found to move to
while(!valid) //while there isn't a valid location, search for one
{
double rand = Math.random();
int[] test = new int[2]; //use to house the next potential location
test[0] = coor[0];
test[1] = coor[1];
if(rand < 0.25) //corresponds to moving north
test[1]++;
else if(rand < 0.5) //moving east
test[0]++;
else if(rand < 0.75) //moving south
test[1]--;
else //moving west
test[0]--;
//next location is valid if it's within the boundaries of the grid
if(test[0] >= 1 && test[0] <= size && test[1] >= 1 && test[1] <= size)
{//if a valid location is found, transfer the coordinate points
coor[0] = test[0];
coor[1] = test[1];
valid = true;
}
}//otherwise, repeat the loop to try to find another valid location
move++; //increment move if a valid move is made
}
//after the end of the game, indicate the total number of moves
System.out.println("Number of moves: " + move);
}
}
MATLAB version:
coor = [1,1];
numMoves = 0;
size = 10;
while ~(coor(1) == size && coor(2) == size)
valid = false;
while ~valid
r = rand;
test = zeros(1,2);
test(1) = coor(1);
test(2) = coor(2);
if r < 0.25
test(2) = test(2) + 1;
elseif r < 0.5
test(1) = test(1) + 1;
elseif r < 0.75
test(2) = test(2) - 1;
else
test(1) = test(1) - 1;
end
if(test(1) >= 1 && test(1) <= size && test(2) >= 1 && test(2) <= size)
coor(1) = test(1);
coor(2) = test(2);
valid = true;
end
end
numMoves = numMoves + 1;
end
numMoves
In subsequent posts, we'll work with this code and add variations.
