Workshop on Basic MatlabParesh Kamble

Types of Flow Control Conditional Control – if, else, switch

Loop Control – for, while, continue, break

Error Control – try, catch

Program Termination – return

Conditional Control – if, else, switch if, else and elseif:

The if statement evaluates a logical expression and executes a group of statements when the expression is true.

The optional elseif and else keywords provide for the execution of alternate groups of statements.

An end keyword, which matches the if, terminates the last group of statements.

Conditional Control – if, else, switch if, else and elseif:

The MATLAB algorithm for generating a magic square of order ninvolves 3 different cases: when n is odd, when n is even but not divisible by 4, or when n is divisible by 4.

This is described by:if rem(n,2) ~= 0

M = odd_magic(n)

elseif rem(n,4) ~= 0

M = single_even_magic(n)

else

M = double_even_magic(n)

end

Conditional Control – if, else, switch if, else and elseif:To check for equality between two variables we use,

It tests where they are equal

A = magic(4);

B = A;

B(1,1) = 0;

A == B

ans = 0 1 1 1

1 1 1 1

1 1 1 1

1 1 1 1

Isequal checks if they are equal

isequal(A, B)

ans = 0

Conditional Control – if, else, switch if, else and elseif:Usually this situation will never go to else state:

if A > B

'greater'

elseif A < B

'less'

elseif A == B

'equal'

else

error('Unexpected situation')

end

Conditional Control – if, else, switch switch and case:The logic of the magic squares algorithm can also be described by:

switch (rem(n,4)==0) + (rem(n,2)==0)

case 0

M = odd_magic(n)

case 1

M = single_even_magic(n)

case 2

M = double_even_magic(n)

otherwise

error('This is impossible')

end

Loop Control – for, while for:

for n = 3:32

r(n) = rank(magic(n));

end

for i = 1:m

for j = 1:n

H(i,j) = 1/(i+j);

end

end

Loop Control – for, while while:a = 0; fa = -Inf;

b = 3; fb = Inf;

while b-a > eps*b

x = (a+b)/2;

fx = x^3-2*x-5;

if sign(fx) == sign(fa)

a = x; fa = fx;

else

b = x; fb = fx;

end

end

Thank you!