Arrays are a fundamental data structure in computer programming. They allow for the storage and manipulation of a collection of elements, making it easier for developers to work with large sets of data. However, there is a curious phenomenon that often catches beginners off guard: the fact that a[5] is equal to 5[a]. This may seem counterintuitive at first glance, but understanding why this is the case can provide insight into the inner workings of arrays. Let's delve deeper into this concept and explore why a[5] and 5[a] are essentially the same thing.
First, let's define what an array is. An array is a data structure that stores a collection of elements in a contiguous memory location. Each element in the array is assigned a unique index, starting from 0. This means that the first element in the array is at index 0, the second element is at index 1, and so on. So, if we have an array called "numbers" with the elements [1, 2, 3, 4, 5], the value of numbers[0] would be 1, numbers[1] would be 2, and so on.
Now, let's look at the syntax of accessing elements in an array. In most programming languages, including C++, Java, and Python, the syntax for accessing an element in an array is array[index]. This means that to access the element at a specific index, we use the array name followed by square brackets containing the index value. So, in the example of the "numbers" array, to access the element at index 3, we would use numbers[3] which would give us the value 4.
But why is it that a[5] is equal to 5[a]? This is because arrays are essentially pointers to memory addresses. When we access an element in an array, the computer calculates the memory location of that element and retrieves its value. So, when we write a[5], the computer calculates the memory location of the 5th element in the array "a" and retrieves its value. Similarly, when we write 5[a], the computer calculates the memory location of the 5th element in the array "5", which doesn't actually exist, and retrieves its value. Since the value of "5" is still "5", 5[a] is essentially the same as a[5].
This concept may seem confusing, but it has practical implications in computer programming. For example, if we wanted to swap the values of two elements in an array, we could use the syntax a[i] = a[j] to swap the values at indices i and j. This is possible because a[i] and a[j] both refer to memory locations, and we are simply assigning the value at one memory location to another. This same logic applies to the syntax a[i] = i[a], which would also swap the values at indices i and a.
In addition, this concept of arrays being pointers to memory addresses is also the reason why arrays have a fixed size. Since arrays need to store elements in a contiguous memory location, the computer needs to know the size of the array beforehand to allocate the necessary memory. This is why we cannot dynamically resize an array once it has been initialized.
In conclusion, the reason why a[5] is equal to 5[a] is due to the fact that arrays are essentially pointers to memory addresses
