Arrays and Matlab programming construts.pptx

Unit 3:
Arrays and MATLAB Programming
Constructs

Relational operations
Symbol Description
< Less than
<= Less than or equal to
> Greater than
>= Greater than or equal
to
== Equal to
~= Not equal to

A = [2 4 6; 8 10 12]
A =
2 4 6
8 10 12
B = [5 5 5; 9 9 9]
B=
5 5 5
9 9 9

A < B
ans =
1 1 0
1 0 0
A > 7
ans =
0 0
0
1 1
1

A = 1:3
A =
1 2 3
B = [2; 3]
B =
2
3
A >= B
ans =
0 1 1
0 0 1

Logical (Boolean) Operations
& Find logical AND
Short-Circuit && Logical AND with short-circuiting
~ Find logical NOT
| Find logical OR
Short-Circuit || Logical OR with short-circuiting
xor Find logical exclusive-OR
find Find indices and values of nonzero elements

A = [5 7 0; 0 2 9; 5 0
0]
A =
5 7 0
0 2 9
5 0 0
B = [6 6 0; 1 3 5; -1 0 0]
B =
6 6 0
1 3 5
-1 0 0
A & B
ans =
1 1 0
0 1 1
1 0 0

Short-Circuit AND, &&
Syntax
expr1 && expr2

Examples
b = 1;
a = 20;
x = (b ~= 0) && (a/b >
18.5)
x =
1

or, |
A = [5 7 0; 0 2 9; 5 0
0]
A =
5 7 0
0 2 9
5 0 0
B = [6 6 0; 1 3 5; -1 0 0]
B =
6 6 0
1 3 5
-1 0 0

A | B
ans = 3×3 logical array
1 1 0
1 1 1
1 0 0

Short-Circuit OR, ||
x = 5
if x < 3 || x > 7
disp('x is outside the range of
3 to 7.');
else
disp('x is within the range.');
End
x is within the range.

xor
>> X = [1 0 0]
X =
1 0 0
>> Y = [0 1
1]
Y =
0 1 1
>> xor(X,Y)
ans =
1 1 1

find
X = [1 0 2; 0 1 1; 0 0
4]
X =
1 0 2
0 1 1
0 0 4
k = find(X)
k = 5×1
1
5
7
8
9

If statement
if <expression>
% statement(s) will execute if the expression is true
<statements>
end
a = 10;
% check the condition using if statement
if a < 20
% if condition is true then print the following
fprintf('a is less than 20n' );
end
fprintf('value of a is : %dn', a);
Result:
a is less than 20
value of a is : 10

if...else statement
if <expression>
% statement(s) will execute if the boolean expression
is true
<statement(s)>
else
<statement(s)>
% statement(s) will execute if the boolean expression
is false
end

Example
a = 100;
% check the condition
if a < 20
% if condition is true then print the following
fprintf('a is less than 20n' );
else
% if condition is false then print the following
fprintf('a is not less than 20n' );
end
fprintf('value of a is : %dn', a);
Result:
a is not less than 20
value of a is : 100

Switch Statement
switch
<switch_expression>
case <case_expression>
<statements>
case <case_expression>
<statements>
...
...
otherwise
<statements>
end

Example
grade = 'B’;
switch(grade)
case 'A’
fprintf('Excellent!n' );
case 'B’
fprintf('Well donen' );
case 'C’
fprintf('Well donen' );
case 'D’
fprintf('You passedn' );
case 'F’
fprintf('Better try againn' );
otherwise
fprintf('Invalid graden' );
End
Result:
Well done

If…elseif…else statement
if condition1
% Statements to execute if 'condition1' is true
elseif condition2
% Statements to execute if 'condition2' is true
else
% Statements to execute if no conditions are met
end

Example
score = 85;
if score >= 90
disp('Grade: A');
elseif score >= 80
disp('Grade: B');
elseif score >= 70
disp('Grade: C');
else
disp('Grade: F');
end

• Write a script file that asks the user for the input of a number and
returns the natural logarithm of the number if the number is positive,
and displays an error message otherwise.
• The cost per kilometre for a rental car is Rs.0.50 for the first 100
kilometres, Rs.0.30 for the next 200 kilometres and Rs.0.20 for all
kilometres in excess of 300 kilometres. Write a function that
determines the total cost for a given number of kilometres.

% Script to compute natural logarithm of a positive number
num = input('Enter a number: ');
if num > 0
ln_val = log(num);
fprintf('The natural logarithm of %g is %gn', num, ln_val);
else
fprintf('Error: The input must be a positive number.n');
end

if km <= 100
cost = 0.50 * km;
elseif km <= 300
cost = (0.50 * 100) + (0.30 * (km - 100));
else
cost = (0.50 * 100) + (0.30 * 200) + (0.20 * (km - 300));
end
end

The for Loop
Syntax
for index = values
<program statements>
...
end

values has one of the following
forms −
Sr.No. Format & Description
1
initval:endval
increments the index variable from initval to endval by 1, and repeats execution of program statements until index is
greater than endval.
2
initval:step:endval
increments index by the value step on each iteration, or decrements when step is negative.
3
valArray
creates a column vector index from subsequent columns of array valArray on each iteration. For example, on the first
iteration, index = valArray(:,1). The loop executes for a maximum of n times, where n is the number of columns
of valArray, given by numel(valArray, 1, :). The input valArray can be of any MATLAB data type, including a string, cell
array, or struct.

Example 1
for a = 10:20
fprintf('value of a: %dn', a);
end

value of a: 10
value of a: 11
value of a: 12
value of a: 13
value of a: 14
value of a: 15
value of a: 16
value of a: 17
value of a: 18
value of a: 19
value of a: 20

Example 2
for a = 1.0: -0.1: 0.0
disp(a)
end

1
0.9000
0.8000
0.7000
0.6000
0.5000
0.4000
0.3000
0.2000
0.1000
0

Example 3
for a = [24,18,17,23,28]
disp(a)
end

The while Loop
Syntax
while <expression>
<statements>
end

a = 10;
% while loop execution
while( a < 20 )
fprintf('value of a: %dn', a);
a = a + 1;
end

value of a: 10
value of a: 11
value of a: 12
value of a: 13
value of a: 14
value of a: 15
value of a: 16
value of a: 17
value of a: 18
value of a: 19

The Nested Loops
Syntax
for m = 1:j
for n = 1:k
<statements>;
end
end

while <expression1>
while <expression2>
<statements>
end
end

Example
rows = 1:10;
cols = 1:10;
% Initialize an empty matrix to store the results
multiplicationTable = zeros(length(rows),
length(cols));
% Outer loop iterates through rows
for a = rows
% Inner loop iterates through columns
for b = cols
% Calculate the product and store it in the
matrix
multiplicationTable(a, b) = a * b;
end
end
% Display the multiplication table
disp('Multiplication Table (1-10):');

Multiplication Table (1-10):
1 2 3 4 5 6 7 8 9
10
2 4 6 8 10 12 14 16 18
20
3 6 9 12 15 18 21 24 27
30
4 8 12 16 20 24 28 32 36
40
5 10 15 20 25 30 35 40 45
50
6 12 18 24 30 36 42 48 54
60
7 14 21 28 35 42 49 56 63
70
8 16 24 32 40 48 56 64 72
80
9 18 27 36 45 54 63 72 81
90

Arrays and Matlab programming construts.pptx

Arrays and Matlab programming construts.pptx

More Related Content

Similar to Arrays and Matlab programming construts.pptx

Recently uploaded

Arrays and Matlab programming construts.pptx