CIS 250 - Arrays

declaring an array for ints: int num[10];
declaring and initializing an array: int num[] = { 1, 2, 3, 4 };
if an array is only partially initialized at declaration, the remaining (uninitialized) elements are set to 0
the name of an array is a pointer to the first element of the array (num is equivalent to &num[0])
you can use pointers to refer to arrays just as you can use subscripts (*(num+2) is equivalent to num[2])
see array1.cpp
arrays can be passed to functions using just the array name since that points to the beginning of the array in memory
changes made to an array in a function change the actual array that was passed since arrays are passed by reference only
you can make sure the contents of a passed array aren't modified by specifying it as a const in the formal argument list for the function
if you want to make sure a function doesn't change the contents of an array, place the keyword const in front of the array parameter in the function definition and prototype
since functions do not know how long an array is, you will usually have to also pass the length of the array
pointer arithmetic works differently than normal arithmetic since the number being added must be multiplied by the size of the data type
For example: if p is an int pointer which points to array n, then p points to element n[0], and p+1 points to element n[1]. If this program is on a machine that has 4 byte ints, the actual value of p+1 is 4 more than p
see array2.cpp

We won't go beyond two-dimensional arrays, which you can think of as a checkerboard or spreadsheet grid (they have rows and columns).
declaring a multidimensional array: int num[2][5];
declaring and initializing amultidimensional array: int num[][] = { {1, 2}, {3, 4} };
When you pass a multidimensional array, you have to specify every dimension except the first.
see array3.cpp
You can play all sorts of games with arrays since the elements of an array occupy contiguous memory locations. See array4.cpp for an example of how a multidimensional array can be manipulated by a function as if it is a one-dimensional aray.
C-style strings are character arrays with a terminating null ('\0') character
It is often easier to use the new string class available in C++.
See array5.cpp for examples of handling string arrays.
See array6.cpp for examples of differences in handling the different types of strings, including sorting and assignment.

parallel arrays refer to two or more arrays where elements at a specific index are all related
parallel arrays are usually considered a poor practice
parallel arrays can be useful at times, and you also have to know how to maintain code that already uses them
parallel arrays can usually be easily replaced by a single array of structs where the struct combines the data that was divided between the arrays