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Matlab Programming TipsPart 2– Input / Output Commands (Review)

by

Shameer Koya

input Command

input - Prompt for user input.Input is the simple basic command to request

the user input. Displays a prompt text for the user to

understand what data to be entered and waits for the user to input a value and press the Return key.  i = input('Enter the current value:') str = input(‘text’,'s') returns the entered text as a

MATLAB string, without evaluating expressions.

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sscanf Command

Read data as string and convert to the other formats based on the definition.

X = sscanf(str, format, size) Reads data from the vector str, converts it according

to the format, and store the results in array X. Argument ‘size’ is optional.

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disp Command

disp - (display) command displays variable values or text on screen Displays each time on new line. Doesn't print variable name disp(variable_name) or disp('text string')

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fprintf Command

fprintf - Means file print formatted'fprintf' is used to formats data and displays

the results on the screen and to write the data in to a text file. Can write to screen or to a file Can mix numbers and text in output Have full control of output display

Basic Syntax is fprintf('Text to display')

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>> fprintf( 'How are you' ) How are you>>

Problem – Command Window displays prompt (>>) at end of text, not at start of next line!

To make the prompt to appear on the start of a new line, \n at the end of the fprintf text

>> fprintf( Electrical Engineering\n' ) Electrical Engineering >>

Use \n in middle of text to make MATLAB display remainder of text on next line

>> fprintf(' Electrical \nEngineering') Electrical Engineering

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fprintf …

To format the display data, the formatting operators are used. 

A formatting operator starts with a percentage sign, %, and ends with a conversion character. 

Common conversion specifiers: %f fixed point (decimal always between 1's and 0.1's

place, e.g., 3.14, 56.8 %e scientific notation, e.g, 2.99e+008 %d integers (no decimal point shown) %s string of characters

>> fprintf( 'Joe is %d weighs %f kilos', age, weight )

>> fprintf( 'Joe weighs %f kilos', n1 )

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fprintf to format the output

fprintf to format the output …

Examples >> age = 35; >> weight = 75.25; >> fprintf( 'Joe is %d weighs %f kilos\n', age, weight ) Joe is 35 weighs 75.250000 kilos >> fprintf( 'Joe weighs %4.4f kilos\n', weight ) Joe weighs 75.2500 kilos >> fprintf( 'Joe weighs %4.2f kilos\n', weight ) Joe weighs 75.25 kilos

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fprintf to format the output…

To display a percent sign, use %% in the text

To display a single quote, use ' ' in the text (two sequential single quotes)

To display a backslash, use \\ in the text (two sequential backslashes)

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