Both icurrent and error are scalars, how can you expect a graph. Try to make vector, so that you can plot.
Here I am trying to show you how vcan you generate plot parameters, please ensure that I have just check the code to generate plot only (Please check the data and changes as per your requirements)
p = 1.23;
Q = input('Flow ');
v = (4*Q)/(pi*0.5^2);
d = 0.5;
u= 1.79*10^(-5);
re = (p*v*d)/u;
xl=.00001;
xu=1;
imax=100;
f =@(x) ((4*log10((re)*sqrt(x)))-.4)-(1/(sqrt(x)));
icurrent=[];
error=[];
icurrent(1)=0;
error(1)= 100;
i=1;
xr=xu-((f(xu)*(xl-xu))/(f(xl)-f(xu)));
disp(' i xl xu xr xro error')
while icurrent(i)<imax
xrOLD=xr;
icurrent(i+1)=icurrent(i)+1;
f(xl);
f(xu);
xr=xu-((f(xu)*(xl-xu))/(f(xl)-f(xu)));
test=f(xr)*f(xl);
if icurrent(i) > 1
error(i+1)= abs(((xr-xrOLD)/xr)*100);
end
if icurrent(i) <= 2
error(i+1)= abs(((xr-xrOLD)/xr)*100);
end
fprintf(1,'\t%g\t%12g\t%12g\t%12g\t%12g\t%12g\n',icurrent(i+1),xl,xu,xr,xrOLD,error(i+1))
if test>0
xl=xr;
end
if test<0
xu=xr;
end
hold on
i=i+1;
end
plot(icurrent,error);
Hope it Helps!
