Given an array Arr of N positive integers. Your task is to find the elements whose value is equal to that of its index value ( Consider 1-based indexing ).

Sure, here is a step-by-step solution in Python:

1. Initialize an empty list to store the elements whose value is equal to their index value.

result = []

2. Iterate over the array using a for loop. The enumerate function can be used to get both the index and value of each element. Remember to add 1 to the index during the comparison because the problem uses 1-based indexing.

for i, num in enumerate(Arr, start=1):
    if i == num:
        result.append(num)

3. Return the result list.

return result

Here is the complete Python function:

def find_elements(Arr):
    result = []
    for i, num in enumerate(Arr, start=1):
        if i == num:
            result.append(num)
    return result

You can call this function with your array as the argument to find the elements whose value is equal to their index value.