Which of the following can be used to determine the number of elements present in an array Arn?

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Beltron Programmer 1 Oct 2023 Official Paper

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Answer 1

The correct answer is Option 2) sizeof(Arr) / sizeof(Arr[0]).

Key Points

In C/C++, sizeof is used to determine the memory (in bytes) occupied by a data type or variable.
To find the number of elements in an array Arr, we use the formula:
sizeof(Arr) / sizeof(Arr[0])
This divides the total size of the array (in bytes) by the size of one element, giving the total number of elements.
Example:
If int Arr[5] = {10, 20, 30, 40, 50};
sizeof(Arr) = 20 bytes (5 integers × 4 bytes each)
sizeof(Arr[0]) = 4 bytes
So, 20 / 4 = 5 elements.

Additional Information

Option 1 – sizeof(Arr[0]): ❌ This only gives the size of the first element, not the total number of elements.
Option 3 – sizeof(Arr): ❌ Gives total size in bytes, not the count of elements.
Option 4 – sizeof(Arr[MAX]): ❌ Incorrect and may even lead to an error if MAX is not defined properly or goes out of bounds.

Conclusion: Use sizeof(Arr) / sizeof(Arr[0]) to correctly determine the number of elements in an array.