Solving a system of 4 linear equations with Gauss Method

I have written a basic code to help solve this problem, but Matlab is giving me an error.

%Gauss Method
clear;clc;format('long','g')
i=1;
x(i)=1;
y(i)=1;
z(i)=1;
t(i)=1;
errorx(i)=9999;
errory(i)=9999;
errorz(i)=9999;
errort(i)=9999;
while errorx(i)>=10^-5 || errory(i)>=10^-5 || errorz(i)>=10^-5 ||errort(i)>=10^-5
    x(i+1) = (2 - y(i) + z(i) - 2*t(i))/5;
    y(i+1) = (1 + z(i) + x(i) - t(i))/4;
    z(i+1) = (3 - x(i) - y(i) - t(i))/5;
    t(i+1) = (4 +2*x(i) - y(i) +2*z(i))/8;
    errorx(i) = abs((x(i+1)-x(i))/x(i));
    errory(i) = abs((y(i+1)-y(i))/y(i));
    errorz(i) = abs((z(i+1)-z(i))/z(i));
    errort(i) = abs((t(i+1)-t(i))/t(i));
    i=i+1;
end

disp([x',y',z',t'])

and the error is

??? Attempted to access errorx(2); index out of bounds because numel(errorx)=1.

Error in ==> gaussmethodas3 at 12 while errorx(i)>=10^-5 errory(i)>=10^-5 errorz(i)>=10^-5 ||errort(i)>=10^-5

[Konstantinos Sofos]

use

    errorx(i+1) = abs((x(i+1)-x(i))/x(i));
    errory(i+1) = abs((y(i+1)-y(i))/y(i));
    errorz(i+1) = abs((z(i+1)-z(i))/z(i));
    errort(i+1) = abs((t(i+1)-t(i))/t(i));

debugging can make you to understand your code. see MATLAB Debugging Tutorial