How to write a square function in Matlab?

Question

I am trying to write a code in Matlab to generate a square function as shown in the attached figure. When I tried coding this in Matlab, I got a trapezoid function instead of a perfect square. Please note that the time at tinjb, tinje, and tend is not an exact multiple of the time step (dt). For reference, I have also included a screenshot of the time and mdotf values that are expected.

i = 2;
tsim = 0;
flag1 = 0;
flag2 = 0;
mdotL(1) = 0;
tout(1) = 0;
mliqtot = 0;

while tsim < tend
dt = 0.7;
tsim = tsim + dt;
if tsim < tinjb
    mdotl = 0;
elseif tsim >= tinjb && flag1 == 0
    dt = tsim - tinjb;
    tsim = tinjb;
    mdotl = 0;
    flag1 = 1;
elseif tsim == tinjb
    mdotl = 1;
elseif tsim > tinjb && tsim < tinje
    mdotl = 1;
elseif tsim >= tinje && flag2 == 0
    dt = tsim - tinje;
    tsim = tinje;
    mdotl = 1;
    flag2 = 1;
elseif tsim == tinje
    mdotl = 0;
else
    mdotl = 0;
end


mliqtot = mliqtot + mdotl * dt;
tout(i, 1) = tsim;
mdotL(i, 1) = mdotl;
i = i + 1;
tsim = tsim + dt;
end

Please help me get this right. This is for my research.

This is what the square function should look like

Time and mdotf values that the Matlab code should spit out

Answer 1

The plot of your code looks like a triangle because of the large timesteps. I think this does everything you explained in your description.

clc; clear all; close all;

tStart = 0; %tsim
tEnd = 5; %tend
tStep = 0.7; %dt
a = 1; %tinjb
b = 2; %tinje
x = tStart:tStep:tEnd;
y = rectangularPulse(a,b,x); %mdotf
subplot(2,1,1); plot(x,y);

syms tSym;
subplot(2,1,2); fplot(rectangularPulse(a,b,tSym), [0 5]);