Question

What is printed by the following code?

int[] arr = {7,2,8,1,5, 8,2,6,10,7};
int sum = 0;
for (int i=0; i < ; i++)
{
sum += arr[i];
i = arr[i];
}
System.out.println("Sum: "+sum);

Answer 1

The code calculates the sum of certain elements in an integer array using a for-loop with a unique index handling. The final output, considering the loop iterates over the entire array, would be "Sum: 23" due to index skipping based on the array's values. This method could also cause exceptions or infinite loops if not implemented properly.

Step-by-step explanation:

The student's question is about determining the output of a given piece of Java code. The code in question is supposed to calculate the sum of an array, but with a twist, where the index is changed during execution. Unfortunately, the code is missing a condition within the for-loop, which should specify the loop's end condition. However, assuming that this is an inadvertent mistake and that the loop should iterate over the entire array, we can deduce the resultant behavior.

The code defines an integer array with specific values. The sum variable is meant to accumulate the values in the array. However, the for-loop contains a unique operation where the index i is set to the value of arr[i] at each iteration. This will lead to an irregular stepping through the array based on the values at each index.

Analyzing the code step-by-step:

• The loop starts at index 0, where arr[0] is 7, so sum becomes 7, and i is set to 7.
• The next iteration steps directly to index 7 (skipping indices 1-6), where arr[7] is 6, so sum becomes 13, and i is set to 6.
• In the next iteration, the loop looks at index 6 (which is actually the previous index in the sequence), where arr[6] is 2, sum becomes 15, and i is set to 2.
• Finally, the loop checks index 2, where arr[2] is 8, sum becomes 23, and i is set to 8.

The loop will end because index 8 is out of the bounds of the loop condition, assuming it was supposed to be i < arr.length.

The output of the provided code, with the corrected for-loop, would therefore be:

Sum: 23

It's crucial to note that such a for-loop can lead to potential array index out of bounds exceptions or infinite loops if not handled correctly within the code.