Java If...Else
Making decisions in your Java programs
🤔 What is Java If...Else?
Java If...Else statements allow your program to make decisions and execute different code blocks based on conditions. They control the flow of your program execution.
// Simple if statement
int age = 18;
if (age >= 18) {
System.out.println("You are an adult!");
} else {
System.out.println("You are a minor!");
}
Output:
You are an adult!
Types of If Statements
Simple If
Execute code if condition is true
if (x > 0) {
System.out.println("Positive");
}If-Else
Choose between two options
if (x > 0) {
System.out.println("Positive");
} else {
System.out.println("Not positive");
}Else If
Multiple conditions to check
if (x > 0) {
System.out.println("Positive");
} else if (x < 0) {
System.out.println("Negative");
} else {
System.out.println("Zero");
}Nested If
If statements inside other if statements
if (x > 0) {
if (x > 10) {
System.out.println("Big positive");
}
}🔹 Basic If-Else Example
Simple decision making with if-else:
public class IfElseExample {
public static void main(String[] args) {
int score = 85;
if (score >= 90) {
System.out.println("Grade: A");
} else if (score >= 80) {
System.out.println("Grade: B");
} else if (score >= 70) {
System.out.println("Grade: C");
} else if (score >= 60) {
System.out.println("Grade: D");
} else {
System.out.println("Grade: F");
}
System.out.println("Your score: " + score);
}
}Output:
Grade: B
Your score: 85
🔹 Multiple Conditions
Using logical operators in if statements:
public class MultipleConditions {
public static void main(String[] args) {
int age = 25;
boolean hasJob = true;
double salary = 50000;
// Multiple conditions with AND
if (age >= 18 && hasJob && salary > 30000) {
System.out.println("Eligible for loan");
} else {
System.out.println("Not eligible for loan");
}
// Multiple conditions with OR
if (age < 18 || salary < 20000) {
System.out.println("Special discount available");
} else {
System.out.println("Regular pricing applies");
}
}
}Output:
Eligible for loan
Regular pricing applies
🔹 Nested If Statements
If statements inside other if statements:
public class NestedIf {
public static void main(String[] args) {
int temperature = 25;
boolean isSunny = true;
if (temperature > 20) {
System.out.println("Weather is warm");
if (isSunny) {
System.out.println("Perfect day for outdoor activities!");
} else {
System.out.println("Warm but cloudy");
}
} else {
System.out.println("Weather is cold");
if (temperature < 0) {
System.out.println("It's freezing!");
} else {
System.out.println("Just a bit chilly");
}
}
}
}Output:
Weather is warm
Perfect day for outdoor activities!
🔹 Ternary Operator
Short form of if-else statement:
public class TernaryOperator {
public static void main(String[] args) {
int age = 20;
// Ternary operator: condition ? value_if_true : value_if_false
String status = (age >= 18) ? "Adult" : "Minor";
System.out.println("Status: " + status);
// Another example
int a = 10, b = 20;
int max = (a > b) ? a : b;
System.out.println("Maximum: " + max);
// Can be used in print statements
System.out.println("You are " + ((age >= 18) ? "eligible" : "not eligible") + " to vote");
}
}Output:
Status: Adult
Maximum: 20
You are eligible to vote