Decision Making in Java

Oct 15, 2024tejasathalye

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Hey there! In this guide, we'll explore decision-making in Java. Decision-making structures allow you to execute different blocks of code based on certain conditions. Let's dive in!

• Decision-making structures allow you to execute different blocks of code based on certain conditions.
• Java provides several constructs for decision-making, including if, else, else if, and switch.

1. The if Statement

Syntax:

if (condition) {
    // code to be executed if condition is true
}

Example:

int num = 10; if (num > 0) {
    System.out.println("The number is positive."); }

2. The if...else Statement

Syntax:

if (condition1) {     // code to be executed if condition1 is true 
    } else {     // code to be executed if condition1 is false 
    }

Example:

int num = -5; if (num > 0) {     
    System.out.println("The number is positive."); } 
    else {     
        System.out.println("The number is not positive."); }

3. The if...else if...else Statement

Syntax:

if (condition1) {     // code to be executed if condition1 is true 
    } else if (condition2) {     // code to be executed if condition2 is true 
    }  else {     // code to be executed if both conditions are false 
    }

Example:

int num = 0; if (num > 0) {     
    System.out.println("The number is positive."); } 
    else if (num < 0) {     
        System.out.println("The number is negative."); }
         else {     
            System.out.println("The number is zero."); }

4. The switch Statement

Syntax:

switch (expression) {     
    case value1:         // code to be executed if expression == value1
    break;     
    case value2:         // code to be executed if expression == value2         
    break;     
    default:         // code to be executed if expression doesn't match any case 
    }

Example:

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;     
    default:         
    System.out.println("Not a valid day"); }

5. Nested if Statements

Example:

int num = 15; if (num > 10) {     
    System.out.println("The number is greater than 10.");     
    if (num > 20) {         
        System.out.println("The number is also greater than 20.");     
        } }

6. Conditional Operators

Java also supports conditional operators for compact decision-making.

Ternary Operator

Syntax:

(condition) ? expression1 : expression2;

Example:

int num = 10; String result = (num > 0) ? "Positive" : "Non-positive";
System.out.println(result);

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Understanding decision-making structures in Java is crucial for controlling the flow of your program and executing different actions based on conditions. Happy coding!