sumandaverage.java

tutorial solutions for java programing

// Exercise 3.4
public class SumAndAverage { // saved as "SumAndAverage.java"
	public static void main(String[] args){
		int sum = 0; // accumulated sum
		double average; // average in double
		int count = 0; // set a counter to count how many numbers to add up in total
		
		//using FOR loop
		for (int i = 1; i <= 100; i++) {
			sum += i;
			count++;
		}
		
		//(a) using WHILE loop
		/*int i = 1;
		while(i <= 100){
			sum += i;
			i++;
			count++;
		}*/
		
		//(b) compute sum and average from 111 to 8989
		/*int i = 111;
		while(i <= 8989){
			sum += i;
			i++;
			count++;
		}*/
		
		// (c) sum the ODD numbers from 1 to 100
		/*for (int i = 1; i <= 100; i++) {
			if (i ==1 || i % 2 != 0){
			sum += i;
			count++;
			}
		}*/
		
		// (d) sum up the integer from 1 to 100 which can be divided by 7
		/*for (int i = 1; i <= 100; i++) {
			if (i >= 7 && i % 7 == 0){
				sum += i;
				count++;
			}
		}*/
		
		//compute the average using the sum divided by the number of integers
		//same for all parts of this question
		average = (double)sum / count;
		System.out.println("The sum is " + sum);
		System.out.println("The average is " + average);
	}
}