programming-for-dummies

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Drawbacks of Arrays
To get around the problem of creating large arrays that aren’t needed, you
can create resizable or dynamic arrays that can grow or shrink as you need
them (see the earlier section, “Working with Resizable Arrays”). Such resizable
arrays can be convenient, but you have to make sure that each time you
resize an array, you don’t accidentally delete data that you want to keep.
Data types
Another limitation of arrays is that they can hold only one data type at a
time. So if you want to store a list of names and numbers, you have to create
two separate arrays:
✦ One array to store the names
✦ Another array to store the numbers
Some programming languages allow you to create a data type called a
variant. A variant data type can hold any type of data, so if you create an
array of variant data types, you can create an array that can hold both
strings and numbers.
Searching and sorting
Another problem with arrays is searching and sorting an array. If you create
an array to hold 10,000 names, how can you find the name Bill Gates
stored in that array? To search for data stored in an array, you have to
search through the entire array from start to finish. For a small array, this
can be acceptable, but searching through an array that contains thousands
of names or numbers can get tedious and slow, especially if you need to
search through an array on a regular basis.
So if an array contains 10,000 names and the name you want is the last element
in that array, you have to search through 10,000 array elements just to
find the name you want.
More cumbersome than searching an array is sorting an array. If you store
10,000 names in an array and suddenly decide you want to sort those names
in alphabetical order, you have to move and sort the entire list one array element
at a time. Doing this once may be acceptable, but doing this on a regular
basis can be cumbersome and slow.
Adding and deleting
Rather than dump all your data in an array and try to sort it out later, you
might want to sort data while you store it. Adding data to an empty array is
easy; dump the data in any array element. The problem comes when you
want to add data in between two array elements.