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Java Expressions: Types, Examples & Practice Questions | Complete Guide


Master Java expressions with comprehensive guide covering arithmetic, relational, logical, assignment, conditional, and ternary expressions with real examples and practice questions.

1️⃣ Arithmetic Expressions

Used for calculations.

int a = 10;
int b = 3;

int sum = a + b;        // 13
int diff = a - b;       // 7
int product = a * b;    // 30
int quotient = a / b;   // 3 (integer division)
int remainder = a % b;  // 1

👉 a + b, a * b, a % b are expressions.

2️⃣ Relational (Comparison) Expressions

Used to compare values. Result is true or false.

int x = 5;
int y = 8;

boolean result1 = x < y;   // true
boolean result2 = x == y;  // false
boolean result3 = x != y;  // true

3️⃣ Logical Expressions

Used to combine conditions.

int age = 20;
boolean hasID = true;

boolean canEnter = (age >= 18) && hasID;  // true

Operators:

  • && → AND
  • || → OR
  • ! → NOT

4️⃣ Assignment Expressions

Assign values to variables.

int num = 10;
num += 5;   // same as num = num + 5 (15)
num *= 2;   // same as num = num * 2 (30)

5️⃣ Unary Expressions

Operate on a single value.

int count = 5;

count++;  // 6 (increment)
count--;  // 5 (decrement)

boolean isOpen = false;
boolean status = !isOpen; // true

6️⃣ Conditional (Ternary) Expression

A shortcut for if-else.

int marks = 75;

String result = (marks >= 50) ? "Pass" : "Fail";

7️⃣ String Expressions

Used with text.

String firstName = "Yasir";
String lastName = "Bhutta";

String fullName = firstName + " " + lastName;
// Yasir Bhutta

8️⃣ Mixed Expressions

Combining different types.

int a = 5;
int b = 2;

double result = a / (double) b;  // 2.5

9️⃣ Expression inside System.out.println()

Very common for beginners.

System.out.println(10 + 5);          // 15
System.out.println("Sum = " + (10 + 5)); // Sum = 15

📝 Practice Questions (Java Expressions)

Q1. What will be the output?

System.out.println(8 + 2 * 5);

Q2. What is the value of result?

int a = 6;
int b = 4;
boolean result = a >= b;

Q3. What will be printed?

int x = 10;
System.out.println(x++ + 5);

Q4. Identify the expression in the statement:

double avg = (a + b + c) / 3.0;

Q5. What is the output?

System.out.println(15 % 4);

Q6. What will be printed?

int num = 5;
System.out.println(num > 3 && num < 10);

Q7. What is the value of status?

int marks = 45;
String status = (marks >= 50) ? "Pass" : "Fail";

Q8. Which operator is used to reverse a boolean value?

boolean flag = false;

Q9. What will be the output?

System.out.println("Result: " + 10 + 20);

Q10. What is the result of this expression?

int result = 20 / 4 + 3 * 2;

🧪 Tasks

🔹 Lab 1: Basic Calculator

Write a Java program that:

  • Declares two integer variables
  • Performs + − × ÷ %
  • Prints all results

🔹 Lab 2: Increment & Decrement

  • Declare an integer variable
  • Apply ++ and --
  • Print values before and after operations

🔹 Lab 3: Even or Odd

  • Take an integer
  • Use an expression to check even or odd
  • Print the result

🔹 Lab 4: Maximum of Two Numbers

  • Declare two numbers
  • Use a ternary expression
  • Print the larger number

🔹 Lab 5: Pass or Fail System

  • Declare marks
  • Print "Pass" if marks ≥ 50, else "Fail"

🔹 Lab 6: Logical Operator Practice

  • Declare age and hasID

  • Allow entry if:

    • age ≥ 18 AND hasID is true

🔹 Lab 7: Simple Interest

  • Declare principal, rate, time
  • Use an expression to calculate simple interest

Formula:

SI = (P × R × T) / 100

🔹 Lab 8: Positive, Negative, or Zero

  • Declare a number
  • Use if-else with expressions
  • Print the result

🔹 Lab 9: String Expression

  • Declare first and last name
  • Combine them using +
  • Print full name

🔹 Lab 10: Operator Precedence Test

  • Write a program using:
int result = 10 + 2 * 3 - 4 / 2;
  • Print and explain the output

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