Review: If statements

What is an if statement?

An if statement allows a program to execute a block of code based on whether a specified condition is true.

Syntax of an if statement

The basic syntax is: if (condition) { // code to execute }

True or false: If statements can only check one condition.

False, because they can chain multiple conditions using else if.

Fill in the blank: 'If x > 10, then ___.'

execute the code block for true condition.

What happens if the condition is false?

If the condition is false, the code block inside the if statement will not execute.

Difference between if and else if

If checks the condition first; else if checks an additional condition if the first is false.

What is an else statement?

An else statement runs a block of code when the associated if condition is false.

Example of a simple if statement

if (temperature > 32) { console.log('It is above freezing.'); }

Nested if statements

You can place an if statement inside another if statement to check multiple conditions.

True or false: Else statements are optional.

True, because an if statement can work without an else.

What do we use comparison operators for?

To evaluate conditions in if statements, such as >, <, ==.

Example of chaining conditions

if (x < 10) { // code 1 } else if (x >= 10 && x < 20) { // code 2 }

True or false: If statements can execute multiple lines of code.

True, because you can include multiple statements inside the braces.

What is a boolean expression?

A boolean expression evaluates to either true or false and is used in if statements.

Comparison: If vs Switch statement

If is for conditions; switch is for multiple discrete values of a variable.

Fill in the blank: 'If it rains, then take an ___.'

umbrella.

What does the else if allow?

It allows checking additional conditions if the previous if is false.