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Java Decision Making: Understanding Conditional Statements and Their Applications

Explore the fundamentals of decision-making in Java programming. Learn how to evaluate conditions using if statements, if-else statements, and switch cases to control the flow of your applications effectively. Enhance your coding skills with clear examples and practical insights into Java's decision-making structures.

Java - Decision Making

Overview of Decision Making

Decision-making structures evaluate one or more conditions in a program and execute specific statements based on whether those conditions are true or false. Below is the general form of a typical decision-making structure found in most programming languages:

Types of Decision Making Statements in Java

Java provides several types of decision-making statements:

Sr.No. Statement & Description
1 if statement: An if statement consists of a boolean expression followed by one or more statements.
2 if...else statement: An if statement can be followed by an optional else statement, which executes when the boolean expression is false.
3 nested if statement: You can use one if or else if statement inside another if or else if statement(s).
4 switch statement: A switch statement allows a variable to be tested for equality against a list of values.

The ? : Operator

The conditional operator ?: can replace if...else statements. Its general form is:

Exp1 ? Exp2 : Exp3;

Where Exp1, Exp2, and Exp3 are expressions. Here's how it works:

  • First, Exp1 is evaluated.
  • If Exp1 is true, the value of Exp2 becomes the value of the whole expression.
  • If Exp1 is false, Exp3 is evaluated, and its value becomes the value of the entire expression.

Example of Decision Making Using the Ternary Operator

In the example below, we create two variables a and b. We use the ternary operator to assign values to b based on the value of a:

Test Class Implementation

public class Test {

public static void main(String args[]) {
    int a, b;
    a = 10;
    b = (a == 1) ? 20 : 30;
    System.out.println("Value of b is : " +  b );

    b = (a == 10) ? 20 : 30;
    System.out.println("Value of b is : " + b );
}
}

Output

Output

Value of b is : 30
Value of b is : 20