1 Lecture 4 Post-Graduate Students Advanced Programming (Introduction to MATLAB) Code: ENG 505 Dr. Basheer M. Nasef Computers & Systems Dept.

In the previous lectures 2  Matlab Windows (workspace, m-file,…)  Working with Arrays  Mathematical Operations with Arrays  Generating Random numbers

Agenda 3  Using Script Files and Managing Data  Input Command  Output Commands: disp, fprintf  Save / load Commands  Importing / Exporting Data.

4  To enable the user to assign a value to the variable in the run-time. This is done by using the input command for creating the variable. Input Command

5  Example: Chapter4 Example4.m Input Command

6  Two commands that are frequently used to generate output are disp and fprintf.  The disp command displays the output on the screen.  The fprintf command can be used to display the output on the screen or to save the output to a file. Output Commands

7  The disp command: disp  Example: PopTable.m Displaying data in a table

8  Example: PopTable.m disp

9  The fprintf command:  Using the fprintf command to display text:  Using the fprintf command to display text and numerical values: fprintf

10 fprintf  – (minus sign): Left-justifies the number within the field.  precision specifies the number of digits to the right of the decimal point.

11  The last element in the formatting elements, which is required, is the conversion character, which specifies the notation in which the number is displayed. Some of the common notations are: fprintf

12  Example: Chapter4Example7.m fprintf \n: moves to a new line

13  Using the fprintf command to save output to a file: When dealing with files, be careful with the path of the file. (it is better to have the file in the current directory) fprintf: saving output to a file

14  Step a: fprintf: saving output to a file file identifier.

15  Step b:  Step c: fprintf: saving output to a file

16  Example 5: fprintf: saving output to a file

17  Example 5: fprintf: saving output to a file

18 fprintf: saving output to a file  Example 5:

19  The save command: you can save all variables in the work space: Save to file All of the variables currently in the workspace are saved in a file named file_name.mat that is created in the current directory. In mat files, which are written in a binary format, each variable preserves its name, type, size, and value. These files cannot be read by other applications.

20  The save command: you can save some variables in the work space:  Saving variables in ascii format: Save to file

21  The load command: is used to retrieve data from (.mat) files (created by save command), ascii files or text (.txt) files.  loading data from (.mat) files: Load from file

22  loading data from text files (.txt): Load from file

23  Import from Excel sheet: Importing and exporting data  Export to Excel sheet:

24 Importing and exporting data  Example: importing data from Excel sheet:

25 Exercise

26 Exercise: solution: m-file

27 Exercise: solution: result in Command Window

28 Exercise Modification Solve the previous exercise but instead of using the input command assume that the values are stored in Vinput.txt file, also save the results in Vresults.txt file.

29 solution: input text file and m-file

30 solution: output text file

Material & problems 31  We have covered Chapter 4 from Gilat.  Problems you can try: Sample Problem 4-1 1,2,5,10,19,22

Assignment #1, Due Date is 19/11/  Problem: 23 in section 4.7, page 130 in Gilat You have to deliver a screen shoot of your Matlab code and result.