how to store output values in a matrix for each output variable?

I want to store output values of x1,g(x) etc in a matrix,plz help me out. here's my program:

function SA()
x1=input('\n enter initial value:-');
acc=input('\n enter accuracy:-');
n=input('\n itterations:-');
while (dg(x1)>1)
    x1=input('\n enter initial value:-');
end
fprintf('\n n  x1  x2 (x2-x1)  g(x1) ');
for i=1:1:n
    x2=g(x1);
    fprintf('\n %d %f %f %f %f',i,x1,x2,abs(x2-x1),g(x1));
    if abs(x2-x1)>acc
        x1=x2;
    else
        fprintf('\n root is %f',x2');
        break;
    end
end
end
function y=g(x)
y=(((x^2)+1)/3);
end
function z=dg(x)
z=((2*x)/3);
end

Answer 1

[Konark Kelaiya]

Initialize another variable say X3 as X3 = []

Then use X3 to store x1 and g(x) values

Modify this portion of code as

X3 = [];
x1=input('\n enter initial value:-');
acc=input('\n enter accuracy:-');
n=input('\n itterations:-');
X3 = [X3 x1];
while (dg(x1)>1)
    x1=input('\n enter initial value:-');
    X3 = [X3 x1];
 end

Then other changes in below portion of Code

 if abs(x2-x1)>acc
        x1=x2;
        X3 = [X3 x1];
    else
        fprintf('\n root is %f',x2');
        X3 = [X3 x2];
        break;
    end

[taher azim]

i made changes accordingly but it didn't work.