Java Programming

Day 8: Java Logical Operators & Conditional Statements

Master logical operators (AND, OR, NOT) and conditional statements (if, if-else, else-if) in Java programming

Today's Learning Objectives

Logical Operators

• AND (&&) operator with truth tables
• OR (||) operator with practical examples
• NOT (!) operator for condition reversal
• Multiple variable declarations

Conditional Statements

• Simple if statements
• if-else conditions
• else-if ladder structures
• Real-world programming examples

Logical Operators in Java

1. AND Operator (&&)

In AND operator, if both conditions are true then we get result is true.

Truth Table

Condition1	Condition2	Result
true	true	true
true	false	false
false	true	false
false	false	false

// Boolean AND Example

boolean

a = true;

boolean

b = true;

boolean

c = false;

boolean

d = false;

System.out.println(a && b); // true
System.out.println(a && c); // false
System.out.println(c && b); // false
System.out.println(c && d); // false

// Integer Comparison AND Example

int

a = 100, b = 150, c = 23, d = 430;

System.out.println((a < b) && (c < d)); // true
System.out.println((a < b) && (c > d)); // false
System.out.println((a > b) && (c < d)); // false
System.out.println((a > b) && (c > d)); // false

2. OR Operator (||)

In OR operator, if any one condition is true then we get result is true.

Truth Table

Condition1	Condition2	Result
true	true	true
true	false	true
false	true	true
false	false	false

// Boolean OR Example

boolean

a = true;

boolean

b = true;

boolean

c = false;

boolean

d = false;

System.out.println(a || b); // true
System.out.println(a || c); // true
System.out.println(c || b); // true
System.out.println(c || d); // false

3. NOT Operator (!)

NOT operator means reverse of original values. If condition is true then result is false, and vice versa.

Truth Table

Condition	Result
true	false
false	true

// NOT Operator Example

boolean

a = true;

boolean

b = false;

System.out.println(a); // true
System.out.println(!a); // false
System.out.println(b); // false
System.out.println(!b); // true

// With comparisons

int

x = 100, y = 23;
System.out.println(x > y); // true
System.out.println(!(x > y)); // false

Multiple Variable Declaration

You can define multiple variables of the same datatype in a single line.

// Syntax

datatype variableName1 = value1, variableName2 = value2, variableName3 = value3;

// Example

int

a = 100, b = 334, c = 345, d = 33;

// Using in logical operations

System.out.println((a <= b) && (c != d)); // true
System.out.println((a <= b) || (c != d)); // true

Java Conditional Statements

There are 2 types of conditional statements in Java: if-else conditions and switch statements. Today we'll focus on if-else conditions.

1. Simple if Statement

If block condition is true then it executes if block of code, otherwise it skips it.

Syntax

if(condition)
{
// Java statements
}

// Example

public class Demo7 {
    public static void main(String[] args) {
        System.out.println("Main method started");

        int a = 100;
        int b = 240;

        if(a < b) {
            System.out.println("Pune...");
        }

        System.out.println("Main method ended");
    }
}

2. if-else Statement

If condition is true, execute if block. If condition is false, execute else block.

Syntax

if(condition) {
// if block code
} else {
// else block code
}

// Example

int a = 100;
int b = 200;

if(a >= b) {
System.out.println("Pune..");
} else {
System.out.println("Mumbai..");
}

3. else if

Multiple conditions checked sequentially. First true condition executes its block and skips remaining conditions.

Syntax

if(condition1) {
    // condition 1 block
} else if(condition2) {
    // condition 2 block
} else if(condition3) {
    // condition 3 block
} else {
    // else block
}

// Find maximum number example

int a = 10000, b = 800, c = 230;

if((a > b) && (a > c)) {
    System.out.println("a is bigger number");
} else if(b > c) {
    System.out.println("b is bigger number");
} else {
    System.out.println("c is bigger number");
}

Real-world Examples

Grade Classification System

int marks = 85;

if(marks < 25) {
    System.out.println("Grade is F");
} else if((marks >= 25) && (marks <= 45)) {
    System.out.println("Grade is E");
} else if((marks >= 46) && (marks <= 55)) {
    System.out.println("Grade is D");
} else if((marks >= 56) && (marks <= 65)) {
    System.out.println("Grade is C");
} else if((marks >= 66) && (marks <= 75)) {
    System.out.println("Grade is B");
} else {
    System.out.println("Grade is A");
}

Day 8 Knowledge Check

Question 1 of 5

What is the result of (true && false) || (false && true)?

Key Takeaways

Logical Operators

AND (&&): Both conditions must be true → result is true
OR (||): Any one condition true → result is true
NOT (!): Reverses boolean value (true ↔ false)
Multiple Variables: int a = 10, b = 20, c = 30;

Truth Tables

AND: T&&T=T, T&&F=F, F&&T=F, F&&F=F
OR: T||T=T, T||F=T, F||T=T, F||F=F
NOT: !T=F, !F=T
Use parentheses for complex expressions

Conditional Statements

if: Execute block only if condition is true
if-else: Execute if block or else block
else if: Multiple conditions, first true executes
Use logical operators in conditions for complex logic

Real-world Applications

Age Categories: Child (1-11), Teen (12-17), Adult (18-64), Senior (65+)
Grade System: F(<25), E(25-45), D(46-55), C(56-65), B(66-75), A(75+)
Number Classification: Small, Medium, Big, Biggest ranges
Decision Making: User input validation, menu systems

💡 Master these logical operators and conditional statements as they form the foundation for decision-making in programming. Day 9 will introduce loops for repetitive operations.

Today's Learning Objectives

Logical Operators

• AND (&&) operator with truth tables
• OR (||) operator with practical examples
• NOT (!) operator for condition reversal
• Multiple variable declarations

Conditional Statements

• Simple if statements
• if-else conditions
• else-if ladder structures
• Real-world programming examples

Logical Operators in Java

1. AND Operator (&&)

In AND operator, if both conditions are true then we get result is true.

Truth Table

Condition1	Condition2	Result
true	true	true
true	false	false
false	true	false
false	false	false

// Boolean AND Example

boolean

a = true;

boolean

b = true;

boolean

c = false;

boolean

d = false;

System.out.println(a && b); // true
System.out.println(a && c); // false
System.out.println(c && b); // false
System.out.println(c && d); // false

// Integer Comparison AND Example

int

2. OR Operator (||)

In OR operator, if any one condition is true then we get result is true.

Truth Table

Condition1	Condition2	Result
true	true	true
true	false	true
false	true	true
false	false	false

// Boolean OR Example

boolean

a = true;

boolean

b = true;

boolean

c = false;

boolean

d = false;

System.out.println(a || b); // true
System.out.println(a || c); // true
System.out.println(c || b); // true
System.out.println(c || d); // false

3. NOT Operator (!)

NOT operator means reverse of original values. If condition is true then result is false, and vice versa.

Truth Table

Condition	Result
true	false
false	true

// NOT Operator Example

boolean

a = true;

boolean

b = false;

System.out.println(a); // true
System.out.println(!a); // false
System.out.println(b); // false
System.out.println(!b); // true

// With comparisons

int

x = 100, y = 23;
System.out.println(x > y); // true
System.out.println(!(x > y)); // false

Multiple Variable Declaration

You can define multiple variables of the same datatype in a single line.

// Syntax

datatype variableName1 = value1, variableName2 = value2, variableName3 = value3;

// Example

int

a = 100, b = 334, c = 345, d = 33;

// Using in logical operations

System.out.println((a <= b) && (c != d)); // true
System.out.println((a <= b) || (c != d)); // true

Java Conditional Statements

There are 2 types of conditional statements in Java: if-else conditions and switch statements. Today we'll focus on if-else conditions.

1. Simple if Statement

If block condition is true then it executes if block of code, otherwise it skips it.

Syntax

if(condition)
{
// Java statements
}

// Example

2. if-else Statement

If condition is true, execute if block. If condition is false, execute else block.

Syntax

if(condition) {
// if block code
} else {
// else block code
}

// Example

int a = 100;
int b = 200;

if(a >= b) {
System.out.println("Pune..");
} else {
System.out.println("Mumbai..");
}

3. else if

Multiple conditions checked sequentially. First true condition executes its block and skips remaining conditions.

Syntax

if(condition1) {
    // condition 1 block
} else if(condition2) {
    // condition 2 block
} else if(condition3) {
    // condition 3 block
} else {
    // else block
}

// Find maximum number example

Real-world Examples

Age Category Classification

Grade Classification System

Key Takeaways

Logical Operators

AND (&&): Both conditions must be true → result is true
OR (||): Any one condition true → result is true
NOT (!): Reverses boolean value (true ↔ false)
Multiple Variables: int a = 10, b = 20, c = 30;

Truth Tables

AND: T&&T=T, T&&F=F, F&&T=F, F&&F=F
OR: T||T=T, T||F=T, F||T=T, F||F=F
NOT: !T=F, !F=T
Use parentheses for complex expressions

Conditional Statements

if: Execute block only if condition is true
if-else: Execute if block or else block
else if: Multiple conditions, first true executes
Use logical operators in conditions for complex logic

Real-world Applications

Age Categories: Child (1-11), Teen (12-17), Adult (18-64), Senior (65+)
Grade System: F(<25), E(25-45), D(46-55), C(56-65), B(66-75), A(75+)
Number Classification: Small, Medium, Big, Biggest ranges
Decision Making: User input validation, menu systems

💡 Master these logical operators and conditional statements as they form the foundation for decision-making in programming. Day 9 will introduce loops for repetitive operations.

Today's Learning Objectives

Logical Operators

Conditional Statements

Logical Operators in Java

1. AND Operator (&&)

Truth Table

2. OR Operator (||)

Truth Table

3. NOT Operator (!)

Truth Table

Multiple Variable Declaration

Java Conditional Statements

1. Simple if Statement

Syntax

2. if-else Statement

Syntax

3. else if

Syntax

Real-world Examples

Age Category Classification

Grade Classification System

Day 8 Knowledge Check

What is the result of (true && false) || (false && true)?

Key Takeaways

Logical Operators

Truth Tables

Conditional Statements

Real-world Applications

SDET Mastery

Today's Learning Objectives

Logical Operators

Conditional Statements

Logical Operators in Java

1. AND Operator (&&)

Truth Table

2. OR Operator (||)

Truth Table

3. NOT Operator (!)

Truth Table

Multiple Variable Declaration

Java Conditional Statements

1. Simple if Statement

Syntax

2. if-else Statement

Syntax

3. else if

Syntax

Real-world Examples

Age Category Classification

Grade Classification System

Day 8 Knowledge Check

What is the result of (true && false) || (false && true)?

Key Takeaways

Logical Operators

Truth Tables

Conditional Statements

Real-world Applications

SDET Mastery