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Streets and houses

Java Syntax, Level 7, Lesson 4

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Can someone say where I am going wrong???

1. Create an array of 15 integers.
2. Populate it with values from the keyboard.
3. Let the array index represent the house number. The array value at a particular index represents the number of people living in the corresponding house.
Houses with odd numbers are located on one side of the street. Those with even numbers are on the other side. Find out which side of the street has more people living on it.
4. Display the following message: "Odd-numbered houses have more residents." or "Even-numbered houses have more residents."

Note:
The house at index 0 is considered even.

5. If the number of residents on each side of the street is the same, then output nothing.

Requirements:

The program must create an array of 15 integers.
The program should read numbers for the array from the keyboard.
The program should display "Odd-numbered houses have more residents." if the sum of odd array elements is greater than the sum of even ones.
The program should display "Even-numbered houses have more residents." if the sum of even array elements is greater than the sum of odd ones.
The program should not output text to the console if the number of residents on each side is the same.

package com.codegym.task.task07.task0706; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* Streets and houses */ public class Solution { public static void main(String[] args) throws Exception { //write your code here int s2 = 0; int s1 =0; int a[] = new int[15]; BufferedReader r = new BufferedReader(new InputStreamReader(System.in)); for(int i = 0;i<15;i++){ String f = r.readLine(); a[i] = Integer.parseInt(f); } int b[] = new int[7]; int c[] = new int[8]; for(int i = 0;i<7;i++){ b[i] = a[i*2]; s1 = s1 + b[i]; } for(int i = 0;i<8;i++){ c[i] = a[(i*2)+1]; s2 = s2 + c[i]; } if(s1>s2){ System.out.println("Even-numbered houses have more residents."); } else{ System.out.println("Odd-numbered houses have more residents."); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

16 April 2019, 18:38

An array of 15 indices has a max index of 14. After reading in the 15 numbers, your third loop attempts to access the 15th index and you are getting an ArrayIndexOutOfBoundsException being thrown. Your second loop only goes to max index of 12. You are mixing up the length of the even numbers vs odd numbers (remember that Arrays start at index 0 and not index 1). Modify lines 19-35 with this code (you can copy and paste, all i did was add sys.out statements). Run your code and this will spit out information that you can read on the console to help step through your code.

System.out.println("Inputs: " + Arrays.toString(a));
for(int i = 0;i<7;i++){
   System.out.print("Second loop cycle: " + i);
   System.out.println(" - Accessing index: [" + (i*2) + "] of value " + a[i*2]);
   b[i] = a[i*2];

   s1 = s1 + b[i];
   System.out.println("Adding value to s1. s1 now equals - " + s1);
}
System.out.println("****************STARTING THIRD LOOP*********************");
for(int i = 0;i<8;i++){
   System.out.print("Third loop cycle: " + i);
   System.out.println(" - Accessing index: [" + (i*2+1) + "] of value " + a[(i*2)+1]);
   c[i] = a[(i*2)+1];

   s2 = s2 + c[i];
   System.out.println("Adding value to s2. s2 now equals - " + s2);
}