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Java Basics
Sectionย 4. Chapterย 2
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bookUsing Loops with Arrays

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How to Iterate Through an Array Using Loops?

Arrays and loops are frequently used in tandem. When dealing with a large array containing 100 or even 1000 elements, manually working with and extracting each element would be impractical. Just imagine how time-consuming it would be to manually fill such an array...

To achieve such tasks, we'll employ loops. In the previous section, we observed that we initially assigned the variable i a value of 0 in the for loop, and array indexing also starts at 0.

Let's say we have a task to display all the elements of an array of type char with a length of 10. Let's examine a code fragment that accomplishes this task:

Main.java

Main.java

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12345678910111213

            
package com.example;

public class Main {
    public static void main(String[] args) {
        // Initializing a char array
        char[] charArray = {'c', 'o', 'd', 'e', 'f', 'i', 'n', 'i', 't', 'y'};
        
        // Printing the array using a for-loop
        for (int i = 0; i < charArray.length; i++) {
            System.out.print(charArray[i]);
        }
    }
}

Let's take a closer look at how the loop iterates over an array:

Main.java

Main.java

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1234567891011121314

            
package com.example;

public class Main {
    public static void main(String[] args) {
        // Initializing the char array
        char[] charArray = {'c', 'o', 'd', 'e', 'f', 'i', 'n', 'i', 't', 'y'};
        
        // Printing the array using a for-loop
        for (int i = 0; i < charArray.length; i++) {
            System.out.println("Now variable i = " + i + ", and value of charArray[" + i + "] = " + charArray[i] + ";");
         // The value of `i` increments with each loop iteration
        }
    }
}
Task

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We have an array with the hours worked by an employee over a number of days. You need to calculate the average number of hours per day and provide feedback based on the result.

  1. Create a method called calculateAverage(int[] workHours) that returns a double.
  2. Inside this method:
    • Determine the length of the array and store it in a variable (e.g., sizeMassive).
    • Use a for loop to iterate over each element of the array.
    • Accumulate the total number of hours into a variable totalHours.
    • After the loop, compute the average by dividing totalHours by the size of the array, casted to double.

Solution

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Sectionย 4. Chapterย 2
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