Day-18: Understanding Return Datatypes in Java

Return Datatypes: A return type specifies what kind of value a method gives back when it finishes running. If a method doesn't return anything, we use void. 1). Returning an Integer public int add(int a, int b) { return a + b; } 2). Returning a String public String greet(String name) { return "Hello, " + name; } 3. public void printMessage(String message) { System.out.println(message); } the return datatype specifies what type of data a method will return, and it must match the actual returned value in the method body. If the method doesn't return anything, use void. Example code for Return Datatype: public class Calculator2 { // Adds two numbers and returns the result public int add(int no1, int no2) { // parameters & int retunr datatype return no1 + no2; } // Multiplies two numbers and returns the result public int multiply(int no1, int no2) { return no1 * no2; } // Divides two numbers, if no2 is not zero public void division(int no1, int no2) { // void return datatype if (no2 != 0) { System.out.println("Division result: " + (no1 / no2)); } else { System.out.println("Cannot divide by zero."); } } public static void main(String[] args) { Calculator2 calc = new Calculator2(); int result = calc.add(10, 20); System.out.println("Addition result: " + result); int multiplyOutput = calc.multiply(result, 2); System.out.println("Multiplication result: " + multiplyOutput); // Create a Calculator3 instance and use the subtractor method Calculator3 calculator3 = new Calculator3(); int subtractor = calculator3.subtractor(result, 5); System.out.println("Subtraction result: " + subtractor); int subtractor1 = calculator3.subtractor(multiplyOutput, 7); System.out.println("Subtraction by 7 result: " + subtractor1); calc.division(result, 2); // } } class Calculator3 { // Subtracts two numbers and returns the result public int subtractor(int no1, int no2) { return no1 - no2; } } Key Takeaways ✔ Every method must declare a return type (or void). ✔ Return types enforce type safety (Java checks compatibility). ✔ void methods are for actions, not computations. ✔ Always return the correct data type (or face compiler errors). Final Thought Understanding return types is crucial for writing correct and reusable Java methods. Whether returning a value or performing an action, always choose the appropriate type to make your code clear and reliable. Note: The formatting and structure were optimized for clarity with AI assistance. --------------------------- End of the Blog ------------------------------

Apr 8, 2025 - 19:49

Day-18: Understanding Return Datatypes in Java

Return Datatypes:
A return type specifies what kind of value a method gives back when it finishes running. If a method doesn't return anything, we use void.

1). Returning an Integer

public int add(int a, int b) {
    return a + b;
}

2). Returning a String

public String greet(String name) {
    return "Hello, " + name;
}

public void printMessage(String message) {
    System.out.println(message);
}

the return datatype specifies what type of data a method will return, and it must match the actual returned value in the method body. If the method doesn't return anything, use void.

Example code for Return Datatype:

public class Calculator2 {

    // Adds two numbers and returns the result
    public int add(int no1, int no2) { // parameters & int retunr datatype
        return no1 + no2;
    }

    // Multiplies two numbers and returns the result
    public int multiply(int no1, int no2) { 
        return no1 * no2;
    }

    // Divides two numbers, if no2 is not zero
    public void division(int no1, int no2) { // void return datatype
        if (no2 != 0) {
            System.out.println("Division result: " + (no1 / no2));
        } else {
            System.out.println("Cannot divide by zero.");
        }
    }

    public static void main(String[] args) {
        Calculator2 calc = new Calculator2();

        int result = calc.add(10, 20);
        System.out.println("Addition result: " + result);

        int multiplyOutput = calc.multiply(result, 2);
        System.out.println("Multiplication result: " + multiplyOutput);

        // Create a Calculator3 instance and use the subtractor method
        Calculator3 calculator3 = new Calculator3();
        int subtractor = calculator3.subtractor(result, 5);
        System.out.println("Subtraction result: " + subtractor);

        int subtractor1 = calculator3.subtractor(multiplyOutput, 7);
        System.out.println("Subtraction by 7 result: " + subtractor1);

        calc.division(result, 2);  // 
    }
}

class Calculator3 {
    // Subtracts two numbers and returns the result
    public int subtractor(int no1, int no2) {
        return no1 - no2;
    }
}

Key Takeaways

✔ Every method must declare a return type (or void).
✔ Return types enforce type safety (Java checks compatibility).
✔ void methods are for actions, not computations.
✔ Always return the correct data type (or face compiler errors).

Final Thought
Understanding return types is crucial for writing correct and reusable Java methods. Whether returning a value or performing an action, always choose the appropriate type to make your code clear and reliable.

Note: The formatting and structure were optimized for clarity with AI assistance.

--------------------------- End of the Blog ------------------------------