1.  Concepts: I/O, conditionals, mod

Read in the year and print whether it is a leap year using (something equivalent to) the rules below:
	Rule 1.  A non-multiple of 4 is not a leap year.
	Rule 2.  A multiple of 4 is a leap year.
	Rule 3.  Rule 2 does not apply to multiples of 100.
	Rule 4.  Rule 3 does not apply to multiples of 400.

Hint:	REM and MOD are MATLAB functions for finding the remainder.  Use HELP
	to check them out.  E.g., rem(x,y) returns the remainder when x is
	divided by y.

-------------------------------------------------------------
% Get input from user
  year = input('Enter a year: ');

% Evaluate and give output
  if (rem(year,4)==0 & (rem(year,100)~=0 | rem(year,400)==0))
	disp('A leap year!');
  else
	disp('Not a leap year!');
  end

=====================================================================

2.  Concepts: I/O, simple matrix manipulation, array arithmetic,
	      MATLAB functions

Annual US fatality rates (per 100 million vehicle miles) on all roads are stored in a file called $rates.dat$ as an n-by-3 matrix:
	- column 1 contains the years
	- column 2 contains the actual rates
	- column 3 contains the model predicted rates
For example, a row in the file $rates.dat$ looks like this:
	1978	3.39	3.31

Write a program that performs the following tasks:
	- read the data in the file $rates.dat$
	- store the actual fatality rates as the vector variable $actual$
	- store the model predicted rates as the vector variable $model$
	- for each year, calculate the percent error of the modeled rate.
	  Percent error is  (|actual-model|/actual)*100
	  Store the percent errors in a vector variable $errors$
	- Calculate the average percent error (for all years)

Potentially useful MATLAB functions:
  INPUT, LOAD, SIZE, ABS, SUM, MEAN

-------------------------------------------------------------
% Load data file and calculate error in fatality rates

% Load data and set variables
  load rates.dat
  actual=rates(:,2);
  model=rates(:,3);

% Calculate errors
  errors = abs(actual-model)./actual*100;
  ave_error = mean(errors);

=====================================================================

3 and 4:  Check your answers using MATLAB

=====================================================================

% 5.  Conditionals, nested conditions

% Write a program that asks the user for a name with 3 letters. Your
% program should store the name in a variable called $name$. The 
% program should output whether the name that the user typed in is:
% in upper case (e.g. TOM), or 
% in lower case (e.g. tom), or 
% in title case (e.g. Tom), or 
% in messy case, which is non of the above (e.g. ToM, TOm, tOm, ...). 
   
% Some help on how to deal with strings:
% Imagine you have a string assigned to a variable, e.g. 
% var='Jen'
% There is a Matlab function called $double$ that converts a string 
% into an array of numbers where each number represents the position 
% of the according letter in the table of ASCII values. Here is a small 
% portion of the table of ASCII values:
% 
%   letter       position            letter       position   
%      A            65                  a            97
%      B            66                  b            98
%      C            67                  c            99
%      D            68                  d           100
%      E            69                  e           101
%      F            70                  f           102
%           ...                              ...
%           ...                              ...
%      U            85                  u            
%      V            86                  v           118
%      W            87                  w           119
%      X            88                  x           120
%      Y            89                  y           121
%      Z            90                  z           122


% If you typed name=double('Jen') in the Command Window then an array 
% containing 3 numbers: 74  101  110 would be stored in w.
% For simplicity, you can assume that any letter that is not uppercase
% (position 65 through 90) is lower case.

name=input('User, please enter a name with 3 letters: ','s')
name=double(name);

% Evaluate all cases given 1st character is in upper case
if name(1)>=65 &  name(1)<=90
   if name(2)>=65 & name(2)<=90
      if name(3)>=65 & name(2)<=90
         disp('Entered name was in upper case!')
      elseif name(3)>=97 & name(3)<=122
         disp('Entered name was in messy case!')
      end
   elseif name(2)>=97 & name(2)<=122
      if name(3)>=65 & name(2)<=90
         disp('Entered name was in messy case!')
      elseif name(3)>=97 & name(3)<=122
         disp('Entered name was in title case!')
      end
   end
% Evaluate all cases given 1st character is in lower case
elseif name(1)>=97 & name(2)<=122
   if name(2)>=65 & name(2)<=90
      disp('Entered name was in messy case!')
   elseif name(2)>=97 & name(2)<=122
      if name(3)>=65 & name(3)<=90
         disp('Entered name was in messy case!')
      elseif name(3)>=97 & name(3)<=122
         disp('Entered name was in lower case!')
      end
   end
end