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Lecture 4

Post-Graduate Students

Advanced Programming (Introduction to

MATLAB)Code: ENG 505

Dr. Basheer M. Nasef

Computers & Systems

Dept.http://www.bmabdelaty.faculty.zu.edu.eg/Default.aspx

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In the previous lectures

Matlab Windows (workspace, m-file,…)

Working with Arrays

Mathematical Operations with Arrays

Generating Random numbers

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Agenda

Using Script Files and Managing Data

Input Command

Output Commands: disp, fprintf

Save / load Commands

Importing / Exporting Data.

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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

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Example: Chapter4 Example4.m

Input Command

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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

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The disp command:

disp

Example: PopTable.m Displaying data in a table

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Example: PopTable.m

disp

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The fprintf command: Using the fprintf command to display text:

Using the fprintf command to display text and numerical values:

fprintf

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fprintf

– (minus sign): Left-justifies the number within the field.

precision specifies the number of digits to the right of the

decimal point.

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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

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Example: Chapter4Example7.m

fprintf

\n: moves to a new line

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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

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Step a:

fprintf: saving output to a file

file identifier.

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Step b:

Step c:

fprintf: saving output to a file

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Example 5:

fprintf: saving output to a file

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Example 5:

fprintf: saving output to a file

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fprintf: saving output to a file

Example 5:

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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.

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The save command: you can save some variables in the work space:

Saving variables in ascii format:

Save to file

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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

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loading data from text files (.txt):

Load from file

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Import from Excel sheet:

Importing and exporting data

Export to Excel sheet:

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Importing and exporting data

Example: importing data from Excel sheet:

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Exercise

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Exercise: solution: m-file

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Exercise: solution: result in Command Window

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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.

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solution: input text file and m-file

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solution: output text file

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Material & problems

We have covered Chapter 4 from Gilat.

Problems you can try:

Sample Problem 4-1

1,2,5,10,19,22

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Assignment #1, Due Date is 19/11/2015

Problem: 23 in section 4.7, page 130 in Gilat

You have to deliver a screen shoot of your Matlab code and result.