# Conditional statements

### Conditional statements

Conditional statements are examples of "branching behavior", and they allow your code to perform different tasks depending on certain conditions.

There are a few different forms:

• if
• if-else/elseif
• switch-case

### "if"

An if statement allows a block of code to be executed only when certain conditions hold.


if a < 10
b = 1
end

• An if statement starts with the "if" keyword.
• A condition follows if.
• It ends with the keyword "end"
• Any list of statements can be included in between.

### if-else

An if block can include alternate choices.


if a < 10
b = 1
else
b = 2
end


### if-else/elseif

An if block can include multiple choices.


if a < 10
b = 1
elseif a < 20
b = 2
else
b = 3
end


### Logical operators

Multiple logical expressions can be combined together using logical operators.

• Logical AND (with short-circuit): &&
• Logical OR (with short-circuit): ||
• Logical NOT ~

if (a > 3) && (a < 10)
b = 1
end


### Let's try

Read the following code and explain what it does.


M = magic(5);
for i = 1:5
for j = 1:5
if M(i,j) < 4
M(i,j) = 0;
elseif M(i,j) < 6
M(i,j) = 1;
else
M(i,j) = 2;
end
end
end


• Count the number of entries in magic(5) that are less than 10 / greater than 20.
• Recreate the following image

### More exercises

Can you recreate this image using "for" and "if"?