# Documentation

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## Conditional Statements

Conditional statements enable you to select at run time which block of code to execute. The simplest conditional statement is an `if` statement. For example:

```% Generate a random number a = randi(100, 1); % If it is even, divide by 2 if rem(a, 2) == 0 disp('a is even') b = a/2; end```

`if` statements can include alternate choices, using the optional keywords `elseif` or `else`. For example:

```a = randi(100, 1); if a < 30 disp('small') elseif a < 80 disp('medium') else disp('large') end```

Alternatively, when you want to test for equality against a set of known values, use a `switch` statement. For example:

```[dayNum, dayString] = weekday(date, 'long', 'en_US'); switch dayString case 'Monday' disp('Start of the work week') case 'Tuesday' disp('Day 2') case 'Wednesday' disp('Day 3') case 'Thursday' disp('Day 4') case 'Friday' disp('Last day of the work week') otherwise disp('Weekend!') end```

For both `if` and `switch`, MATLAB® executes the code corresponding to the first true condition, and then exits the code block. Each conditional statement requires the `end` keyword.

In general, when you have many possible discrete, known values, `switch` statements are easier to read than `if` statements. However, you cannot test for inequality between `switch` and `case` values. For example, you cannot implement this type of condition with a `switch`:

```yourNumber = input('Enter a number: '); if yourNumber < 0 disp('Negative') elseif yourNumber > 0 disp('Positive') else disp('Zero') end```