Why does this not plot?

It runs through the loop and ends, but it doesn't plot.

function [t]=HW7_JAS_1(P,k,C)
t_lower=0;%lower guess
t_upper=100;%upper guess
t_error=abs(1-((t_upper)/(t_lower)));%error
it=1;%iteration
while t_error >= .0005
    t_mid=(t_lower+t_upper)/2;%calculates root
    t_error=abs(1-((t_upper)/(t_lower)));%calculates new error
    lower_b=(C*exp(k*t_lower))-P;%f(lower bound)
    upper_b=(C*exp(k*t_upper))-P;%f(upper bound)
    froot=(C*exp(k*t_mid))-P;%f(root) 
    if lower_b * froot<0%checks if root is in the lower interval
        t_upper=t_mid;%if it is switches upper guess to root
    elseif upper_b * froot <0%checks if root is in the upper interval
        t_lower=t_mid;%if it is switches lower guess to root
    elseif lower_b * froot ==0%checks if the lower bound*root=0
        t=t_mid;%if is then the that is the root
    else
        t_lower=t_lower-t_upper;
        t_upper=t_upper*2;
    end
    plot(it,t_mid,'g*')
    hold on%allows each point to plotted
    xlabel('Iterations')
    ylabel('Estimated time values')
    legend('Bisection Method')
    it=it+1;%new iteration count
end

Thanks for any help

[dpb]

Don't see why it shouldn't give a scatter plot if it points; unfortunately we have no data so can't run it to see what happens locally.

[Jacob Savona]

Never mind it runs fine. But thanks anyway.