An interactive introduction to MATLAB

50 decision making

executed if all the logical expressions for the precedingelseifandif

commands return false.

Listing 4.7 presents a simple of example of decision making using theif,else,

andelseiffunctions. Copy and paste the example into a new script file, and

run it to see the results for yourself.

Listing 4.7: number_test.m - Script to test sign and magnitude of numbers

1 % number_test.m

2 % Script to test sign and magnitude of numbers

3 %

4 % Craig Warren, 08/07/2010

6 % Variable dictionary

7 % x Variable to hold entered number

9 clear all; % Clear all variables from workspace

10 clc; % Clear command window

12 x = input('Enter a number: '); % Get a number from the user

13 if x<0 % Test if x is negative

14 disp('Your number is a negative number')

15 elseif x<100 % Otherwise test if x is less than 100

16 disp('Your number is between 0 and 99')

17 else % Otherwise x must be 100 or greater

18 disp('Your number is 100 or greater')

19 end

Comments:

• On Line 12 theinputcommand is used, which prompts the user for input
  with the requestEnter a number:and assigns the number entered to
  the variablex.


• On Lines 14, 16, and 18 thedispcommand is used, which simply displays
  text to the Command Window.