Examples

1. Create a vector with the squares of the numbers 1 through 10.

   1 2 4 9 16 25 36 49 64 81 100

         for n = 1 : 10
             squares(n) = n ^ 2 ;
         end

   This works! Notice that we could, but we don't need to use the element-wise power operator since the value of n is always a scalar.

2. Read height and weight data from a file named player_data.txt and display the player number and BMI for each player in the data file. Use a for-loop to compute and display every player's information.

   For example, in a file named team_bmi.m, enter this code:

   % Get the data from the file
   data = load('player_stats.txt');    % loads the player data in the variable data
   [R C] = size(data);                 % Get the number of rows R and columns C 
   
   % Do a little error checking to make sure that we have enough data to continue
   if C < 4 
       error('Not enough player data to continue. Each row needs: num ft in lbs');
   end
   
   % Process each row in the data file
   for r = 1 : R
       num = data(r,1);                % Get the player's number from the data matrix
       ht  = data(r,2)*12 + data(r,3); % Get the player's height (in)
       wt  = data(r,4);                % Get the player's weight (lbs) 
       bmi = BMI_standard(ht,wt);      % Call the BMI_standard function to calculate
   
       % Create user-friendly output
       disp( [ 'Player #' num2str(num) ' has a BMI of ' num2str(bmi) ] );
   end
   

   Some things to notice in our example code:

   • The function BMI_standard must exist and be defined to calculate the BMI when the inputs are the height in inches and the weight in pounds. Reminder:
   • Used the size function to find the number of rows and columns of the data matrix. Use these values to make sure that there is enough data to process. Display an error message and exit if there is not enough data.
   • Used the disp command to display both text and numerical information. To produce that output, you need to use the num2str function to change the numbers to strings so they will display properly.
   • Finished making the program user friendly, by using semicolons to hide all of the intermediate answers that occur before and inside the for loop where you output the BMIs.

   Be sure to run and test the program on different data files to see if everything is working as you want it.