03 - Control Flow If Statements

Programs need to make decisions. If statements let your code choose different paths based on conditions.

Basic If Statement

The simplest form checks one condition;

int health = 20;

if (health > 10) {
    System.out.println("You are healthy!");
}

Structure

if (condition) {
    // code to execute if condition is true
}

If-Else Statements

Choose between two paths:

int health = 5;

if (health > 10) {
    System.out.println("You are healthy!");
} else {
    System.out.println("You need healing!");
}

If-Else Else-If Chain

Check multiple conditions in sequence:


int health = 7;

if (health > 15) {
    System.out.println("You are in great shape!");
} else if (health > 5) {
    System.out.println("You are okay.");
} else {
    System.out.println("You need healing!");
}

Nested If Statements

You can place if statements inside other if statements:

int health = 12;

if (health > 10) {
    if (health > 15) {
        System.out.println("You are in great shape!");
    } else {
        System.out.println("You are healthy!");
    }
} else {
    System.out.println("You need healing!");
}

Compound Conditions

You can combine multiple conditions using logical operators:


// AND - both must be true
int health = 12;
boolean hasPotion = true;

if (health > 10 && hasPotion) {
    System.out.println("You are healthy and have a potion!");
} else if (health > 10) {
    System.out.println("You are healthy but need a potion!");
} else {
    System.out.println("You need healing!");
}

// OR - at least one must be true

int health = 8;
boolean hasPotion = false;
if (health > 10 || hasPotion) {
    System.out.println("You are either healthy or have a potion!");
} else {
    System.out.println("You need healing and a potion!");
}

// NOT - reverses the condition

int health = 8;
if (!(health > 10)) {
    System.out.println("You need healing!");
} else {
    System.out.println("You are healthy!");
}

Ternary Operator

A compact way to assign values:

int health = 12;
String status = (health > 10) ? "Healthy" : "Needs Healing";

Syntax

variable = (condition) ? valueIfTrue : valueIfFalse;

03 - Control Flow If Statements

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