Matlab Commands: Input/Output and Formatting Commands

Input/Output Commands

disp	Displays contents of an array or string.
fscanf	Read formatted data from a file.
format	Controls screen-display format.
fprintf	Performs formatted writes to screen or file.
input	Displays prompts and waits for input.
;	Suppresses screen printing.

Format Codes for fprintf and fscanf

%s	Format as a string.
%d	Format as an integer.
%f	Format as a floating point value.
%e	Format as a floating point value in scientific notation.
%g	Format in the most compact form: %f or %e.
\n	Insert a new line in the output string.
\t	Insert a tab in the output string.

Matlab Commands: Commands for Managing a Session

Clc	Clears Command window.
clear	Removes variables from memory.
exist	Checks for existence of file or variable.
global	Declares variables to be global.
help	Searches for a help topic.
lookfor	Searches help entries for a keyword.
quit	Stops MATLAB.
who	Lists current variables.
whos	Lists current variables (long display).

Related links:

• Matlab Operators: Operators and Special Characters

Matlab Commands: Operators and Special Characters

+	Plus; addition operator.
-	Minus; subtraction operator.
*	Scalar and matrix multiplication operator.
.*	Array multiplication operator.
^	Scalar and matrix exponentiation operator.
.^	Array exponentiation operator.
\	Left-division operator.
/	Right-division operator.
.\	Array left-division operator.
./	Array right-division operator.
:	Colon; generates regularly spaced elements and represents an entire row or column.
( )	Parentheses; encloses function arguments and array indices; overrides precedence.
[ ]	Brackets; enclosures array elements.
.	Decimal point.
…	Ellipsis; line-continuation operator.
,	Comma; separates statements and elements in a row.
;	Semicolon; separates columns and suppresses display.
%	Percent sign; designates a comment and specifies formatting.
_	Quote sign and transpose operator.
._	Nonconjugated transpose operator.
=	Assignment (replacement) operator.

Embedding a watermark image into a cover image using Matlab program

Find below the Matlab codes to embed a watermark image into a cover(host) image:

clear all; close all; clc;

[filename1,pathname]=uigetfile('*.*','Select the host image'); 
image1=imread(num2str(filename1));
imshow(image1); title('Original image');% orginal image for watermarking

[ori_row,ori_col]=size(image1)
host_length=ori_row*ori_col;

i=1;
j=1;
k=1;

[filename2,pathname]=uigetfile('*.*','Select the watermark image'); 

wmimage=imread(num2str(filename2));
[wm_row,wm_col] = size(wmimage);
imshow(wmimage); title('Watermark image');

wm=dec2bin(wmimage);
wm_length=wm_row*wm_col*8;

host=dec2bin(image1);

counter=0; 

while i < host_length
        
        counter=counter+1;
        
        if counter > wm_length
            break;
        end
        
        host(i,8)=wm(j,k);
        k=k+1;
        
        if k>8
            k=1;
            j=j+1;
        end
        
        i=i+1;
end

    key1=wm_row
    key2=wm_col
   
im1=bin2dec(host);
im1=reshape(im1,ori_row,ori_col);
image1(1:ori_row,1:ori_col)=im1(1:ori_row,1:ori_col);

display 'After embed';

imwrite(image1,'wmarked.bmp'); % saves the watermarked image as a bmp file
imshow(image1);title('Watermarked image');

Some Simple Matlab Exercises - Code Samples I

Some Simple Matlab Exercises - Code Samples I

You may find some Matlab Commands here - http://jayitsecurity.blogspot.com/2013/01/matlab-commands-operators-and-special.html

Write a pseudocode and matlab program which receive a positive integer value as input and then output the following message “Even Number” or “Odd Number”.

Example:

Input:           Enter a number: 7

Output:        Odd number

Input:           Enter a number: 8

Output:        Even number

Answer:

Pseudocode

Start

Read input Num

                x = Modulus (Num, 2)

                If x equals 0

                                then display Num is an even number

                Else

                                display Num is an odd number

End

Matlab program

Num = input('Enter a positive integer number: ')

x = mod(Num,2);

if x == 0

    sprintf('%d is an even number', Num)

   

else

    sprintf('%d is an odd number', Num)

   

end

Sample outputs

Enter a positive integer number: 5

ans =

5 is an odd number

Enter a positive integer number: 8

ans =

8 is an even number

Write the expression of matlab language which is equivalent with the following mathematical expressions:

a.     b² – 4ac

b.     (a + b) (c + d) (e + f)

Answer:

a.     b*b – 4*a*c

b.     (a + b)*(c + d)*(e + f)

A chemist uses the decision table below to determine whether a solution is very acidic, acidic, neutral, alkaline, or very alkaline. Write a program that will read in the value of pH for a solution and display its type.

Table 1

pH range	Liquid types
>12 8 – 12 7 3 – 6 <= 2	very alkaline alkaline neutral acidic very acidic

Answer:

clear all, clc

pH = input('Enter pH value: ');

if pH>12

            sprintf('Liquid Type: Very Alkaline')

elseif pH>=8 & pH<=12

            sprintf('Liquid Type: Alkaline')

elseif pH==7

            sprintf('Liquid Type: Neutral')

elseif pH>=3 & pH<=6

            sprintf('Liquid Type: Acidic')

else

            sprintf('Liquid Type: Very Acidic')

end

Sample outputs

Enter pH value: 1

ans =

Liquid Type: Very Acidic

Enter pH value: 11

ans =

Liquid Type: Alkaline

Enter pH value: 7

ans =

Liquid Type: Neutral

Write a program which accepts input time in second and then output it in hour, minute and second.

Example:

Enter time in second: 3770

3770 seconds = 1 hour 2 minutes 50 seconds.

Answer:

Matlab program

clear all, clc;

InputSeconds = input('Enter time in seconds: ');

Seconds = mod(InputSeconds,60);

Bal_Seconds = InputSeconds - Seconds;

Hours = int8(Bal_Seconds/3600);

Minutes = int8(mod(Bal_Seconds,3600)/60);

sprintf('%d second(s) = %d hour(s) %d minute(s) %d second(s)',InputSeconds,Hours,Minutes,Seconds)

Sample outputs

Enter time in seconds: 3770

ans =

3770 second(s) = 1 hour(s) 2 minute(s) 50 second(s)

Enter time in seconds: 7281

ans =

7281 second(s) = 2 hour(s) 1 minute(s) 21 second(s)

Enter time in seconds: 325

ans =

325 second(s) = 0 hour(s) 5 minute(s) 25 second(s)