how i can use x(t) & ... in my program

i use this code but matlab show me an eror how i can fix this eror

also i want plot (>) with angle fee how i can do that ?

clear all
      t=0;
      x(t)=input('Enter X(0) =');
      y(t)=input('Enter Y(0) =');
      fee(t)=input('Enter Fee(0) =');
      for (x(t+1)~=10)&&(fee(t+1)~=90)
      t=t+1;
            plot(x(t),y(t),'>');
          x(t+1)=x(t)+cos(fee(t)+teta(t))+sin(teta(t))*sin(fee(t));
          y(t+1)=y(t)+sin(fee(t)+teta(t))-sin(teta(t))*cos(fee(t));
          fee(t+1)=fee(t)-asin((2*sin(teta(t)))/4);

        end

Answer 1

[Walter Roberson]

MATLAB does not permit the value 0 to be used as a vector index. Vector indexes must be integers 1 or greater.

Requesting '>' as the plot marker gets you a right-pointing triangle. If you want an open arrow instead, then you will need to draw in the markers yourself at each location.

Answer 2

[behnam]

thank you but now i receive this message : ??? Attempted to access x(2); index out of bounds because numel(x)=1.

[Walter Roberson]

If, hypothetically, MATLAB allowed x(0) to be defined, then you would still have had this problem anyhow, because of your line

for (x(t+1)~=10)&&(fee(t+1)~=90)

which, besides being syntactically invalid for a "for" loop, would attempt to access x(1) at a time when only x(0) had been defined.

Your code is non-functional in such a manner that we cannot make a reasonable guess about what you were attempting to write.

Answer 3

[behnam]

i mean i edited my m-file code as below :

please if possible edit my m-file into correct

clear all
      t=1;
      x(t)=input('Enter X(0) =');
      y(t)=input('Enter Y(0) =');
      fee(t)=input('Enter Fee(0) =');
      plot(x(t),y(t),'>');
      i=1;
      if (x(t)~=10)&&(fee(t)~=90)

            x(t+1)=x(t)+cos(fee(t)+teta(t))+sin(teta(t))*sin(fee(t));
            y(t+1)=y(t)+sin(fee(t)+teta(t))-sin(teta(t))*cos(fee(t));
            fee(t+1)=fee(t)-asin((2*sin(teta(t)))/4);
            plot(x(t+1),y(t+1),'>');
            t=t+1;
          end

[Walter Roberson]

Do you want a "while" loop instead of "if" ? If so then you would move the plot() to after the "while" and would

plot(x, y, '>')

However! See

http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

as otherwise your loop might never terminate.