Java Language - 8 - Expressions and Statements

Java Fundamentals – Expressions and Statements

Introduction

Expressions and statements are the building blocks of Java programs. Expressions are combinations of values, variables, and operators, while statements are the fundamental units of code that perform actions and control the flow of your program. In this guide, we’ll delve into expressions, statements, and their importance in Java.

Expressions in Java

Expressions are core elements of Java that produce values. They can be as simple as a single variable or as complex as a combination of operators, variables, and constants. Here’s an example of a basic expression:


int x = 5;
int y = 3;
int result = x + y; // The expression x + y produces the value 8

In this code, the expression ‘x + y’ is evaluated and produces the value 8, which is stored in the ‘result’ variable.

Statements in Java

Statements are complete lines of code that perform actions or control the program’s flow. In Java, each statement typically ends with a semicolon. Here’s an example of a simple statement:


int age = 30; // This is a statement that declares a variable and assigns a value

This statement declares an ‘age’ variable and assigns the value 30 to it.

Assignment Statements

Assignment statements are used to assign values to variables. They are one of the most common types of statements in Java:


int length = 10;
double price = 19.99;
String name = "John";

Assignment statements play a crucial role in storing and manipulating data in your programs.

Conditional Statements

Conditional statements, such as ‘if’ and ‘switch,’ control the flow of your program based on specific conditions. They allow you to execute different code blocks depending on the condition’s result. Here’s an example of an ‘if’ statement:


int score = 85;

if (score >= 70) {
    System.out.println("You passed the exam!");
} else {
    System.out.println("You need to study harder.");
}

Conditional statements are essential for making decisions in your Java programs.

Loop Statements

Loop statements, like ‘for,’ ‘while,’ and ‘do-while,’ enable you to execute a block of code repeatedly. They are used when you need to perform a task multiple times. Here’s an example of a ‘for’ loop:


for (int i = 0; i < 5; i++) {
    System.out.println("Iteration: " + i);
}

Loop statements are crucial for automating repetitive tasks.

Expression Statements

Expression statements combine expressions and statements. They consist of an expression followed by a semicolon and are often used to perform a single action. Here’s an example:


int result = add(5, 3); // The add function is called as an expression statement

Expression statements are used to call functions or methods and store the result in a variable.

Conclusion

Expressions and statements are the fundamental elements of Java programming that allow you to create complex and dynamic applications. Understanding how to construct expressions and use various types of statements is essential for building functional and efficient Java programs.

Java Language – 8 – Expressions and Statements