% Example using a "for" loop to calculate interest.
% Brian Hornbuckle, January 18, 2011.

clear;

principal = 5000;     % will invest $5000.

years = 20;     % let's say that the money will be invested
                % for 20 years and interest is compounded yearly
               
rate = 5;       % interest rate, %

sum = zeros(years,1);        % initialize variable to hold sum after each year

for k = 1:years
    
    if (k == 1)
        
        sum(k) = principal;       % first year put money in the bank but there is no interest
    
    else
        
        sum(k) = sum(k-1) + (rate/100)*sum(k-1);      % interests compounds every year after first year
    
    end;
    
end;

sum         % amount of money in bank at end of each year