Java Basics

Conditionals

Learning Outcome

Implement nested decision logic

Use if–else–if for conditions

Apply if statements correctly

Identify types of control statements

Understand purpose of control statements

Use switch for cleaner code

Imagine you’re driving a car on the road.
You don’t drive randomly—you make decisions at every moment.

If the traffic light is red, you stop.

If it’s green, you move forward.
While the road continues, you keep driving.

Each decision decides when to stop, go, or continue.
Similarly, programs use rules to control their execution flow.

Without rules, a car would move randomly, causing confusion and accidents.
In the same way, without control statements, a Java program would simply run line by line without thinking or deciding.

But real programs need to:

Make decisions based on conditions

Repeat tasks when needed

Choose different paths for different situations

This is where Java Control Statements come in.

They allow a program to pause, decide, repeat, or jump based on given conditions—just like a driver responding to traffic signals, turns, and road signs.

What are Control Statements

Control statements are like traffic rules for a program—they control the flow by deciding what to execute, when to execute it, and how many times it should run.

Looping

Statements

Types of Control Statements

Conditional statements

Jump

statements

Conditional statements – used to choose between alternatives

Example : Traffic Light (Decision Making)

If the light is green

If the light is yellow

If the light is red

Looping statements – used to repeat a set of statements

Example: A teacher taking attendance in a class

The teacher calls each student’s name one by one

This process repeats for every student

The teacher stops when all students are checked

Just like this, loops repeat a task until a condition is satisfied.

Jump statements – used to skip or stop execution

Jump statements are like an emergency exit:

You are watching a movie

Suddenly, the fire alarm rings
You immediately leave the hall, skipping everything else

Conditional Statements

These statements allow for code to be executed based on whether a condition is true or false

if-else

statement

if statement

else if ladder

switch

statement

IF STATEMENT

The Java if statement is used to check a condition.

If the condition is true, the code inside the if block executes.
If the condition is false, the code inside the block does not execute.

Syntax:

if (condition) {

// code runs only when the condition is true

}

For example

If the door is locked, use the key

Condition:

Door is Locked

Action:

Use key

Working of IF STATEMENT

What is if-else-if ladder

The if–else–if ladder is a decision-making control statement used when multiple conditions are checked one after another, and only one block of code executes.

Example : Imagine a teacher assigning grades based on marks:

Example : Imagine a teacher assigning grades based on marks:

The conditions are checked from top to bottom.
once a condition is true, its grade is given and the rest are skipped.

Nested If-Else statement

A nested if means placing one if–else inside another if–else.
It is used when conditions depend on each other and must be checked step by step.

Example: ATM Transaction

If yes → Transaction Successful

Else → Incorrect PIN

If the card is inserted

Then check if the PIN is correct

Else → Please insert card

Switch Case Statement

A switch–case statement is used when you need to choose one action from many options.
It checks a single value and executes the case that matches that value.