1. Introduction To Matlab Class 2
Instructors: Hristiyan (Chris) Kourtev
and Xiaotao Su, PhD
Double click the matlab icon
When prompted click “Skip”

2. Character Vectors And Numeric Vectors
'hello world' is referred to as a character string or a character vector
[35, 26.3, 11, 4] is a numeric vector
These are the two main data types in matlab h e l o w r d
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11) 35
26.3 11 4
(1)
(2)
(3)
(4)

3. Character Vectors (aka Strings) And Numeric Vectors
How to convert between these two data types? What if I have a string, '39.5' and I want to add to it?
num2str & str2num
str2num('39.5') + 5
['hello w', 'orld']
a = [3, 9];
b = [12.6, 8];
[a, b]
c = ['1', num2str(39.5)]
str2num(c) + 200

4. Formatting strings with sprintf
result = sprintf(format_string, input1, input2 …)
Format string: [flags][width][.precision][length] specifier
Common Specifiers: %c character %s string %d integer %e or %E scientific notation %f floating point m = 44.5; k = ‘hello world’ res = sprintf(‘%s, it is %d degrees outside’, k, m); res will be “hello world, it is 44.5 degrees outside”

5. Formatting strings with sprintf
Flags: - left justify; default is right 0 left pads the number with zeroes if padding specified
Width: just a number
Precision: just a number
Examples sprintf('%01.2f', 12.4); %outputs sprintf('%010.2f', 12.4); %outputs sprintf('%.3e',  ); %outputs 3.625e+8
For further reference go to:

6. Taking inputs Create a new program called math.m % math.m %
% Carries out a series of calculations on two
% numbers
% written by Your Name July 2010

7. clear all;
%take inputs
num1=input('what is the first number?');
num2=input('what is the second number?');
%show calculations
disp([num2str(num1), '+', num2str(num2), '=', num2str(num1+num2)]);
disp([num2str(num1), '-', num2str(num2), '=', num2str(num1-num2)]);

8. boolean expressions == > >= < <= & | equals greater than
Boolean expressions either return 1 for true or 0 for false
Possible operators: ==
>
>=
<
<=
& |
equals
greater than
greater than or equal to
less than
and or

9. Note: Put operations inside parenthesis so they are preformed first.
1==1
(1 + 1)==2
(5 + 5) < 10
(5 + 5) <=10
(1 == 1) & (2==3)
(1 == 1) | (2==3)
5 + (5 < 10)
Note: Put operations inside parenthesis so they are preformed first.

10. Conditionals (if statements)
if(Boolean Expression)
do something
end
you can also do this:
if(boolean expression)
else
do something else
or this:
if(boolean expression)
do something
elseif(boolean expr2)
do something else
end

11. Back to math.m if ( (round(num1)==num1) & (round(num2)==num2) )
disp('num1 and num2 are integers')
end

12. if ( (round(num1)==num1) & (round(num2)==num2) )
disp('num1 and num2 are integers')
elseif(round(num1)==num1)
disp('only num1 is an integer')
elseif(round(num2)==num2)
disp('only num2 is an integer')
else
disp('neither number is an integer')
end

13. Task 1 == > >= < <= & | equals greater than
Have math.m tell me which number is larger then the other
“the biggest number is …” ==
>
>=
<
<=
& |
equals
greater than
greater than or equal to
less than
and or

14. Tic and toc tic starts a timer
toc tells you the number of seconds since when you ran toc

15. While loop while is a type of loop that runs while a condition is true
while(boolean statement)
%do something many times
end
%you would stop repeating the loop when the
%boolean statement is false OR if you use
%break

16. While program tic loops = 0; while(toc<5) loops = loops+1;
disp(['number of loops = ', num2str(loops)]);
disp(['number of seconds = ', num2str(toc)]);
end

17. While program stopping after 10 loops
tic
loops = 0;
while(toc<5)
loops = loops+1;
disp(['number of loops = ', num2str(loops)]);
disp(['number of seconds = ', num2str(toc)]);
if(loops>=10)
break;
end