First download the code and save it in a file called 
      bisection.m
in some directory, say in a directory called 
      NUMERICS

Then open MATLAB in the directory NUMERICS and type the commands you see in the "diary" file at 

      http://www.math.ou.edu/~npetrov/diary_bisection.txt

After you type a command in MATLAB, simply press "return" to execute it.  
If you type a semicolumn (;) after a command, the computer will execute it, but will not display the output.  

The command

      bisection( inline('2/pi*exp(2*x/pi)+(1-exp(1))*cos(x)'), 0.0, pi/2, 1.0e-5, 100, 1)

computes and gives as an output the value of a zero of the function 

      f(x)=2/pi*exp(2*x/pi)+(1-exp(1))*cos(x), 

or, in other words, the value of a solution of the equation 

      2/pi*exp(2*x/pi)+(1-exp(1))*cos(x) = 0 , 

in the interval [0,pi/2].  

The tolerance (i.e., the precision with which the code will return the root) is 1.0e-5, i.e., 0.00001.  
If the code cannot find a solution after 100 iterations, it will stop and will return an error message.  
The last argument is 1, which tells the code to print out the intermediate results.  

Instead of calling the function f(x) by using the "inline" sintax, you can equivalently save this function 
in a separate file.  Let's decide to call this function "myfunction", then we have to save in a file called 
      myfunction.m
(in the same directory as the file bisection.m).  The file myfunction.m should look like this 
(the content of the file is what is between the two lines): 

------------------------------------------------------------
function y = myfunction (x)

y = 2/pi*exp(2*x/pi)+(1-exp(1))*cos(x);
------------------------------------------------------------

In that file the empty second line is added just to make the file look prettier; removing this line 
will have no effect.  Once you have saved the file myfunction.m, type on the MATLAB command line 

     bisection( 'myfunction', 0.0, pi/2, 1.0e-5, 100, 1)

and the output will be the same as from the call of the program "bisection" by using "inline".  

You can also call the code using a "handle" to the function "myfunction": 

     bisection( @myfunction, 0.0, pi/2, 1.0e-5, 100, 1) .

Some things to explore:  

*  Compare the results of the above run with the result of running
       bisection( 'myfunction', 0.0, pi/2, 1.0e-14, 100, 0)
   - what is different?  

*  Finally, if you try to execute
       bisection( 'myfunction', 0.0, pi/2, 1.0e-20, 100, 0)
   the computer will complain that you are too greedy.