Core Java: Steps of Java Programming

The steps in writing a Java program is illustrated as follows:

Step 1: Write the source codes (.java) using a programming text editor (such as Notepad++, Textpad, gEdit) or an IDE (such as Eclipse or NetBeans).

Step 2: Compile the source codes (.java) into Java portable bytecode (.class) using the JDK compiler ("javac").

Step 3: Run the compiled bytecode (.class) with the input to produce the desired output, using the Java Runtime ("java").

Below is a simple Java program that demonstrates the three basic programming constructs: sequential, loop, and conditional.

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/*  * Sum the odd numbers and the even numbers from a lowerbound to an upperbound  */ public class OddEvenSum {  // Save as "OddEvenSum.java"    public static void main(String[] args) {       int lowerbound = 1, upperbound = 1000;       int sumOdd  = 0;    // For accumulating odd numbers, init to 0       int sumEven = 0;    // For accumulating even numbers, init to 0       int number = lowerbound;       while (number <= upperbound) {          if (number % 2 == 0) {  // Even             sumEven += number;   // Same as sumEven = sumEven + number          } else {                // Odd             sumOdd += number;    // Same as sumOdd = sumOdd + number          }          ++number;  // Next number       }       // Print the result       System.out.println("The sum of odd numbers from " + lowerbound + " to " + upperbound + " is " + sumOdd);       System.out.println("The sum of even numbers from " + lowerbound + " to " + upperbound + "  is " + sumEven);       System.out.println("The difference between the two sums is " + (sumOdd - sumEven));    } }

The expected outputs are:

The sum of odd numbers from 1 to 1000 is 250000

The sum of even numbers from 1 to 1000  is 250500

The difference between the two sums is -500