in command window;
%part a)
n=-10:1:10;
subplot(3,1,1)
stem(stepDT(n))
subplot (3,1,2)
stem(stepDT(n-3))
subplot(3,1,3)
y1=conv(stepDT(n), stepDT(n-3))
stem(y1, 'g')

%part b)
n=-10:1:10;
subplot (3,1,1)
stem(((1/2).^n).*stepDT(n-2))
subplot (3,1,2)
stem(stepDT(n))
subplot (3,1,3)
y2=conv(((1/2).^n).*stepDT (n-2), stepDT (n))
stem(y2, 'm')

%part c)
n=-10:1:10;
subplot (3,1,1)
stem((-1).^n)
subplot(3,1,2)
stem ( (2.^n).* (stepDT (-1* n+2) ))
subplot (3,1,3)
y3=conv((-1).^n, (2.^n).* (stepDT(-1*n+2)))
stem(y3, 'm')

%part d)
t=-10:1:10;
subplot(3,1,1)
plot(u(t)-u(t-2))
subplot(3,1,2)
plot(u(t))
subplot (3,1,3)
y4=conv(u(t)-u(t-2),u(t))
plot (y4, 'c')

%part e)
t=-10:1:10;
subplot(3,1,1)
plot(exp(-1*t).*u(t))
subplot(3,1,2)
plot(exp(-3*t).*u(t))
subplot(3,1,3)
y5=conv(exp(-1*t).*u(t), exp (-3*t).*u(t))
plot (y5, 'y')

% Easy way
clear all
clc
n=-10:1:10;

x=[1 0 2 3 4 -1 0 2];
h=[1 0 0 -1 -2 1];
y1=conv(x,h)

% Detailed way
clear all
clc
x=[1 0 2 3 4 -1 0 2];
x_=x;
h=[1 0 0 -1 -2 1];
h_=h;
m=zeros(length(x)+length(h)-1); 

for i=1:length(h)
for j=1:length(x)
m(i,j)=x(j)
end
x=[0 x]
end

for i=1:length(h)
k(i,:)=h(i)*m(i,:)
end
sum(k)

subplot (3,1,1)
stem(x_)
title('Function x')
grid on
subplot (3,1,2)
stem(h_)
title( 'Function h')
grid on
subplot (3,1,3)
stem (sum (k) )
title ('Convolution of x and h')
grid on

% Continuous Time Convolution
clear all
clc
t = -10:0.01:10;
x = (t >= -1 & t < 2);
y = (t >= 1 & t < 2);

subplot(3,1,1)
plot(t, x)
title('Function x')

subplot(3,1,2)
plot(t, y)
title('Function y')

subplot(3,1,3)
plot(conv(x, y))
title('Convolution function of x and y')