Matlab 3D plot using arrays in if/else

[this town]

Dear fellows,

I am trying to plot a 3D graph, determining the x and y values using an array and the z values using if/else. This is the code I am playing with but I can't get it to work:

xmin=-1000;
xmax=1000;
division=1.0;
num=((xmax-xmin)/division)+1;

for i=1:(num/2);
x(i)=i-(num/2);
for k=1:(num/2);
y(k)=k-(num/2);
for j=1:10:(num/2);
u(j)=j-num/2;
v(j)=j+6-num/2;
if ((x(i)>=u(j))&&(x(i)<=v(j))&&(x(i)<1000)&&(x(i)>0)&&(y(k)>0)&&(y(k)<1000)) |((x(i)>-1000)&&(x(i)<0)&&(y(k)>-1000)&&(y(k)<1000))|((x(i)>0)&&(x(i)<1000)&&(y(k)>-1000)&&(y(k)<0));
z(i,k)=1.0;
else
z(i,k)=0.0;
end
end
end
end

surf(x,y,z)

I am very new to this so any help would be very valuable, thanks!

 

[Jhero]

It looks like you are attempting to create a 3D graph with x and y values determined by an array and the z values determined by an if/else statement. Unfortunately, your code has some issues that need to be corrected before it will work. First, you need to define the size of the arrays used for x and y. To do this, you can use the "num" variable you created as the size for both of these arrays. You can then use a loop to populate each array with the appropriate values. Second, you need to ensure that your if/else statement is correctly written. You have two separate conditions in the if statement that should be combined using the logical operator "and". Additionally, you should include parentheses around each condition to ensure that your statement is evaluated correctly. Finally, you need to make sure that the variables used in the if/else statement are correctly referenced. In particular, you should use the array indices to reference the x and y values, rather than the values themselves. Once all of these issues have been addressed, you should be able to generate a 3D graph with the desired result. Good luck!