Chapter 4: Programming in Matlab - College of the Redwoods

Section 4.2 Control Structures in Matlab 299
4.2 Control Structures in Matlab
In this section we will discuss the control structures offered by the Matlab
programming language that allow us to add more levels of complexity to the
simple programs we have written thus far. Without further ado and fanfare, let’s
begin.
If
If evaluates a logical expression and executes a block of statements based on
whether the logical expressions evaluates to true (logical 1) or false (logical 0).
The basic structure is as follows.
if logical_expression
statements
end
If the logical_expression evaluates as true (logical 1), then the block of statements
that follow if logical_expression are executed, otherwise the statements
are skipped and program control is transferred to the first statement that follows
end. Let’s look at an example of this control structure’s use.
Matlab’s rem(a,b) returns the remainder when a is divided by b. Thus, if a is
an even integer, then rem(a,2) will equal zero. What follows is a short program
to test if an integer is even. Open the Matlab editor, enter the following script,
then save the file as evenodd.m.
n = input(’Enter an integer: ’);
if (rem(n,2)==0)
fprintf(’The integer %d is even.\n’, n)
end
Return to the command window and run the script by entering evenodd at
the Matlab prompt. Matlab responds by asking you to enter an integer. As a
response, enter the integer 12 and press Enter.
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