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Summary - Conditionals

Combine if, else if, switch and ternary to write a day-of-week app.

Summary - Conditionals

In this group you learned conditionals:

  • if: single condition
  • else/else if: alternative branches
  • nested if: multiple conditions together
  • switch: multi-branch (case/break/default)
  • ternary: one-line condition

These structures let the program make decisions. Now combine them and write a day-of-week app.

Practice Day name (switch)

Write a Main class with a main method. Assign 3 to int day. With switch (day) print "Monday" for case 1:, "Tuesday" for case 2:, "Wednesday" for case 3:. Add break; after each case.

Sample solution

Main.java
public class Main {
    public static void main(String[] args) {
        int day = 3;
        switch (day) {
            case 1:
                System.out.println("Monday");
                break;
            case 2:
                System.out.println("Tuesday");
                break;
            case 3:
                System.out.println("Wednesday");
                break;
        }
    }
}

Expected output

Wednesday

Practice Greeting (if/else if/else)

Write a Main class with a main method. Assign 14 to int hour. With if (hour < 12) print "Good morning", else if (hour < 18) print "Good day", else print "Good evening".

Sample solution

Main.java
public class Main {
    public static void main(String[] args) {
        int hour = 14;
        if (hour < 12) {
            System.out.println("Good morning");
        } else if (hour < 18) {
            System.out.println("Good day");
        } else {
            System.out.println("Good evening");
        }
    }
}

Expected output

Good day

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Which structure best picks a branch by specific values?

  • while
  • switch Correct answer
  • for
  • Scanner

Explanation: switch branches by specific values.

2 Match the conditional structures

Term Meaning
if Condition
switch Multi-branch
? Ternary
else Fallback

3 Complete the ternary

Question 
int x = 10;
String s = (x > 0) ? "Positive" : ____;
Answer 
int x = 10;
String s = (x > 0) ? "Positive" : "Negative";

Explanation: When the condition is false, "Negative" is assigned.

All lessons in Beginner

1 Java basics

  1. What is Java?
  2. The main method
  3. Comments
  4. Class skeleton
  5. javac and java
  6. Summary - Java basics

2 Variables

  1. int and double
  2. boolean
  3. String
  4. Naming variables
  5. final variables
  6. Summary - Variables

3 Data types

  1. Primitive types
  2. Type casting
  3. String concatenation
  4. Math class
  5. BigInteger and BigDecimal
  6. Summary - Data types

4 Project: Calculator

  1. Project design
  2. Add/subtract
  3. Multiply/divide
  4. Error handling
  5. Putting it together

5 Operators

  1. Arithmetic
  2. Comparison
  3. Logical
  4. Bitwise
  5. Assignment and increment
  6. Summary - Operators

6 String basics

  1. length and charAt
  2. equals and equalsIgnoreCase
  3. indexOf and substring
  4. toUpperCase and trim
  5. String.format
  6. Summary - String basics

7 Conditionals

  1. The if statement
  2. else and else if
  3. Nested if
  4. switch
  5. Ternary
  6. Summary - Conditionals

8 Loops

  1. The for loop
  2. The while loop
  3. do-while
  4. break and continue
  5. for-each
  6. Summary - Loops

9 Project: Shopping cart

  1. Cart design
  2. Adding items
  3. Calculating totals
  4. Updating quantity
  5. Putting it together

10 Arrays

  1. Declaring arrays
  2. Array access
  3. Filling arrays
  4. Multi-dimensional arrays
  5. Copying arrays
  6. Summary - Arrays

11 Array methods

  1. Arrays.sort
  2. Arrays.toString
  3. Arrays.binarySearch
  4. Arrays.copyOf
  5. Arrays.fill
  6. Summary - Array methods

12 Collections

  1. ArrayList
  2. add and get
  3. HashMap
  4. put and get
  5. HashSet
  6. Summary - Collections

13 Methods

  1. Defining methods
  2. return
  3. void methods
  4. Method overloading
  5. Scope
  6. Summary - Methods

14 Method parameters

  1. Primitive parameters
  2. Object parameters
  3. varargs
  4. Multiple values via array
  5. final parameters
  6. Summary - Method parameters

15 Project: To-do CLI

  1. Task model
  2. Adding tasks
  3. Listing tasks
  4. Completing tasks
  5. Putting it together

16 String builder

  1. StringBuilder
  2. append
  3. insert and delete
  4. reverse
  5. toString
  6. Summary - String builder

17 Input and output

  1. Scanner
  2. nextInt and nextLine
  3. System.out.printf
  4. BufferedReader
  5. try-with-resources
  6. Summary - Input and output

18 Enum

  1. Declaring enums
  2. values and valueOf
  3. Enum fields
  4. Enum methods
  5. switch with enum
  6. Summary - Enum

19 Exception basics

  1. try/catch
  2. finally
  3. throw
  4. Exception hierarchy
  5. Multiple catch
  6. Summary - Exception basics

20 Beginner final

  1. Project design
  2. Data model
  3. Business logic
  4. Error handling
  5. Putting it together