Key Concepts

Review core concepts you need to learn to master this subject

if Statement

else Statement

else if Statements

Nested Conditional Statements

AND Operator

The OR Operator

NOT Operator

Conditional Operators - Order of Evaluation

if Statement

if (true) {
	System.out.println("This code executes");
}
// Prints: This code executes

if (false) {
	System.out.println("This code does not execute");
}
// There is no output for the above statement

An if statement executes a block of code when a specified boolean expression is evaluated as true.

Conditionals and Control Flow
Lesson 1 of 2
  1. 1
    Introduction to Control Flow
    Imagine we’re writing a program that enrolls students in courses. - If a student has completed the prerequisites, then they can enroll in a course. - Else, they need to take the prerequisit…
    Start
  2. 2
    If-Then Statement
    The if-then statement is the most simple control flow we can write. It tests an expression for truth and executes some code based on it. if (flip == 1) { System.out.println(“Heads!”); } - …
    Start
  3. 3
    If-Then-Else
    We’ve seen how to conditionally execute one block of code, but what if there are two possible blocks of code we’d like to execute? Let’s say if a student has the required prerequisite, then t…
    Start
  4. 4
    If-Then-Else-If
    The conditional structure we’ve learned can be chained together to check as many conditions as are required by our program. Imagine our program is now selecting the appropriate course for a stude…
    Start
  5. 5
    Nested Conditional Statements
    We can create more complex conditional structures by creating nested conditional statements, which is created by placing conditional statements inside other conditional statements: if (outer con…
    Start
  6. 6
    Switch Statement
    An alternative to chaining if-then-else conditions together is to use the switch statement. This conditional will check a given value against any number of conditions and run the code block where t…
    Start
  7. 7
    Review
    Before this lesson, our code executed from top to bottom, line by line. Conditional statements add branching paths to our programs. We use conditionals to make decisions in the program so that di…
    Start

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