Calculating Sum of Array Elements in Java

The provided Java program calculates the sum of all integer elements within an array. Let's break down the code to understand how it achieves this.

public class SumOfArray{
  public static void main(String[ ] args) {
        int [ ] arr = new int [ ] {1, 2, 3, 4};
        int sum  = 0;
        for (int i = 0; i < arr.length; i++)
        {
            sum = sum + arr[i];
        }
        System.out.println("Sum of all the elements of an arry: " + sum);

    }
}

Code Analysis: Summing Array Elements

The program starts by defining a class named SumOfArray with a standard main method, which is the entry point for Java applications.

• Array Initialization: An integer array named arr is declared and initialized with the values {1, 2, 3, 4}. This array contains four elements.
• Sum Variable Initialization: An integer variable named sum is declared and initialized to 0. This variable will store the cumulative sum of the array elements.
• Iteration using For Loop: A for loop is used to iterate through each element of the array.
  • The loop starts with an index i initialized to 0, which is the index of the first element.
  • The loop continues as long as i is less than arr.length (which is 4). This ensures the loop visits indices 0, 1, 2, and 3.
  • In each iteration, the current element arr[i] is added to the sum variable (sum = sum + arr[i];).
  • The loop variable i is incremented by 1 after each iteration (i++).
• Printing the Result: After the loop finishes, the program executes System.out.println("Sum of all the elements of an arry: " + sum);. This statement prints a string followed by the final value stored in the sum variable to the console. Note the minor typo "arry" in the string literal, but this doesn't affect the calculation.

Step-by-Step Execution for Sum of Array Elements

Let's trace the execution of the loop and see how the sum variable changes:

The loop continues as long as i < 4. When i becomes 4, the condition i < arr.length (4 < 4) is false, and the loop terminates.

Output Generation

After the loop finishes, the final value of the sum variable is 10. The program then prints the string "Sum of all the elements of an arry: " concatenated with the value of sum.

Therefore, the complete output printed to the console will be:

Sum of all the elements of an arry: 10

Comparing this with the options, we look for the string "Sum of all the elements of an array: " followed by the number 10. Option 2 matches this value, correcting the typo in the source code's literal string. The case of "Sum" also matches. Option 3 has a different sum (12) and lowercase "sum". Option 1 has a different sum (9). Option 4 is incorrect as the program compiles and runs without errors. The typo "arry" in the print statement is just a string literal issue, not a compilation error.

Verification of Options for Array Sum

• Option 1: "Sum of all the elements of an array: 9" - Incorrect, the calculated sum is 10.
• Option 2: "Sum of all the elements of an array: 10" - Correct, matches the calculated sum and the print statement structure (ignoring the minor typo 'arry' vs 'array' which is a common variation in options).
• Option 3: "sum of all the elements of an array: 12" - Incorrect, the calculated sum is 10, and the output string starts with uppercase "Sum".
• Option 4: "Error" - Incorrect, the code is syntactically correct Java and will compile and run.

Final Answer Explanation

The Java program successfully iterates through the array {1, 2, 3, 4} and adds each element to the sum variable, which starts at 0. The sum accumulates as 1, then 1+2=3, then 3+3=6, and finally 6+4=10. The program then prints a string followed by this final sum. The output is "Sum of all the elements of an arry: 10", which corresponds to option 2 (allowing for the 'arry'/'array' variation and case matching).

Revision Table: Java Array Sum Code

Additional Information: Java Arrays and Loops

Understanding arrays and loops is fundamental in Java programming.

• Arrays: An array is a data structure that stores a fixed-size sequential collection of elements of the same data type. Elements are accessed using an index, starting from 0.
• Declaring and Initializing Arrays: Arrays can be declared using dataType[] arrayName; and initialized either explicitly like new dataType[] {value1, value2, ...}; or by size like new dataType[size];.
• For Loop: The for loop is commonly used to iterate a specific number of times, making it ideal for processing arrays where the number of iterations (equal to the array length) is known beforehand. The structure is for (initialization; condition; increment/decrement) { // loop body }.
• Accessing Array Elements: Individual elements in an array are accessed using the array name followed by the index in square brackets, e.g., arr[0] accesses the first element.