Computer Science 202
Introduction to Programming
Fall 2013, The College of Saint Rose
Sum2ToNBy2 BlueJ Project
Click here to download a BlueJ project for Sum2ToNBy2.
Sum2ToNBy2 Source Code
The Java source code for Sum2ToNBy2 is below. Click on a file name to download it.
/*
* Example Sum2ToNBy2: sum the even integers from 2 to some specified upper limt
*
* Jim Teresco, The College of Saint Rose, CSC 202, Fall 2012
*
* $Id: Sum2ToNBy2.java 2228 2013-10-24 05:42:15Z terescoj $
*/
import java.util.Scanner;
public class Sum2ToNBy2 {
public static void main(String[] args) {
// we'll read the upper limit from the keyboard
Scanner keyboard = new Scanner(System.in);
// the upper limit should be an even number greater than 0
int upperLimit = 0;
while (upperLimit <= 0 || upperLimit % 2 != 0) {
System.out.print("Enter an even positive integer for the upper limit of our sum: ");
upperLimit = keyboard.nextInt();
if (upperLimit <= 0) {
System.out.println("Make it positive!");
}
else if (upperLimit % 2 != 0) {
System.out.println("Make it even!");
}
}
// now we are ready to compute the sum
// initialize to 0 to start
int sum = 0;
// count by 2's up to our limit:
// notice we are initializing our number to 2, we continue
// as long as number is less than or equal to the
// upper limit, and we add 2 to the number each time around
// using our += shorthand notation for number = number + 2
for (int number = 2; number <= upperLimit; number += 2) {
// shorthand to add number to sum
sum += number;
}
// and print our result
System.out.println("Our sum is " + sum);
}
}