If-Else Statements

Beginner ~15 min read

Control flow allows your program to make decisions. The most basic building block of decision making is the if statement.

The `if` Statement

The if statement tells Java to execute a block of code only if a specific condition is true.

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

The `else` Block

Use else to specify a block of code to be executed if the condition is false.

if (age >= 18) {
    System.out.println("You are an adult.");
} else {
    System.out.println("You are a minor.");
}

The `else-if` Ladder

When you have multiple conditions to check, use else if. Java checks them in order properly.

if (score >= 90) {
    grade = 'A';
} else if (score >= 80) {
    grade = 'B';
} else {
    grade = 'C';
}

public class ControlFlowIf {
    public static void main(String[] args) {
        int score = 85;

System.out.println("Score: " + score);

// Simple If-Else
        if (score >= 50) {
            System.out.println("Result: Pass");
        } else {
            System.out.println("Result: Fail");
        }

// Else-If Ladder (Grading System)
        char grade;
        if (score >= 90) {
            grade = 'A';
        } else if (score >= 80) {
            grade = 'B';
        } else if (score >= 70) {
            grade = 'C';
        } else if (score >= 60) {
            grade = 'D';
        } else {
            grade = 'F';
        }
        System.out.println("Grade: " + grade);

// Nested If
        boolean hasLicense = true;
        boolean hasCar = false;

if (hasLicense) {
            if (hasCar) {
                System.out.println("You can drive your car.");
            } else {
                System.out.println("You need to rent a car.");
            }
        } else {
            System.out.println("You need a license used.");
        }
    }
}

Output

Click Run to execute your code

Common Pitfalls

Missing Braces

Java allows omitting braces {} if there is only one line of code. Avoid this practice. It leads to bugs if you add a second line later and forget to add braces.

// BAD (Dangerous)
if (isLogged)
    System.out.println("Welcome");

// GOOD (Safe)
if (isLogged) {
    System.out.println("Welcome");
}

Summary

Use if to execute code based on a condition.
Use else for the alternative path.
Use else if for multiple conditions.
Always use curly braces {} to group your code blocks cleanly.

Previous Operator Precedence

Next Switch Statements →

The if Statement

The else Block

The else-if Ladder