What should I do in order to make my code plot like this?

sap = input('Select a program: 1. Arts; 2. Science; 3. Engineering: ');
nb(1) = 2000;
mir = 0.0625/12;
mc = 200;
for B = 2 : 216
    nb(B) = (nb(B-1)+1) + ((nb(B-1)+1) * mir) + mc;
end
fprintf('At the end of 18 years you will have saved $ %f \n',nb(B))

if sap == 1
    os1(1) = 5550;
    air = 0.07;
    for A = 2 : 22
        os1(A) = (os1(A-1) + 1) + ((os1(A-1) + 1) * air);
    end
    x1 = os1(19)+ os1(20) + os1(21) + os1(22);
    fprintf('The cose of a 4-year college tuition fee is $ %f\n',x1)
    if nb(216) > x1
        disp('Congratulations!!!! You have saved enough.')
    elseif nb(216) < x1
        s1 = x1 - nb(216);
        fprintf('The saving is $ %f\n',s1)
    end
end

I need the year be exactly 0 to 18 years, so I can compare two lines like this.

I tried to use

time = 1:18
plot(time,nb(1:216),time,os1(1:22))

But this will cause erroe message 'Vector must be the same length.'

Can someone please help me with this?

Answer 1

[Mathieu NOE]

hi

this is the modified code

sap = input('Select a program: 1. Arts; 2. Science; 3. Engineering: ');
nb(1) = 2000;
mir = 0.0625/12;
mc = 200;
for B = 2 : 216     % 216 = nb of monthes for 18 years
    nb(B) = (nb(B-1)+1) + ((nb(B-1)+1) * mir) + mc;
end
fprintf('At the end of 18 years you will have saved $ %f \n',nb(B))

if sap == 1
    os1(1) = 5550;
    air = 0.07;
    for A = 2 : 22
        os1(A) = (os1(A-1) + 1) + ((os1(A-1) + 1) * air);
    end
    x1 = os1(19)+ os1(20) + os1(21) + os1(22);
    fprintf('The cose of a 4-year college tuition fee is $ %f\n',x1)
    if nb(216) > x1
        disp('Congratulations!!!! You have saved enough.')
    elseif nb(216) < x1
        s1 = x1 - nb(216);
        fprintf('The saving is $ %f\n',s1)
    end
    
% plot
x_axis_years = 1:18;        % define x axis 
ind_nb_years = (1:18)*12;
nb_years = nb(ind_nb_years);

plot(x_axis_years,nb_years,'-+b',x_axis_years,x1*ones(1,length(x_axis_years)),'r'); grid on
title('my Title');
xlabel('Years');

end