Gunman

How do i do it ?

Gunman

Nvm..I got it ..I will change it ..

Gunman

I can't seem to edit my post so next time when i post i would use code tags ..

anant_tickoo

use code tag like this [ C O D E ] your code [/ C O D E ]

just do't use spaces in code tage. its like html code.

or click # sign in ur advance windows of reply post.

Mjordan2nd

Hope this help a little: http://programmingforums.org/forum/s...ead.php?t=1644

It's C but I hope it should still help.

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lectricpharaoh

The main use of arrays is to manipulate a set of things (objects or variables) that are all of the same type. This allows you to write the code to do the manipulation once, rather than once for each value. You can then loop through, starting with the first element you wish to process, and ending at the last.

Remember that arrays are always zero-based; that is, the first element is element zero, not element one, and the last is numbered as one less than the size. This means if you're looping through an array, make sure you don't go beyond the bounds; the compiler does not check if you exceed the bounds of the array, so you have to do this yourself. Nor does your program throw an exception at runtime, as a Java program will. Note that, in some special circumstances, you actually will want to go beyond the boundaries you've declared for your arrays (the only case I can think of offhand is when you use an array as the last element of a structure, and then dynamically allocate memory for your structure plus some 'extra'), but cases like this are rare, and when you do it, be sure you know why you're doing it.

In C and C++, arrays and pointers are closely related. A pointer is a variable that stores an address of something else (an object, variable, or function), and an address is just the location at which it resides in memory. Pointers are useful because you can access a chunk of memory through the pointer, which is often more efficient. For example, let's assume my system has ints that are 32 bits, and pointers that are 32 bits (this is a very common scenario on modern machines). Now let's say I have an array of 1024 ints. If I pass the whole array (ie, each value separately), that is a lot of parameters I have to pass, and consequently, a lot of work that needs to be done every time the function gets called. On the other hand, I could pass a single pointer to the start of the array, and the called function could then access the entire array through this pointer.

C and C++ support this sort of coding by having arrays and pointers be somewhat interchangeable. The idea is that any array name without a subscript (the number in the brackets), or with fewer subscripts than the array actually has (ie, one subscript for a two-dimensional array) is treated as an address. As such, you can assign it to a pointer, and you can use array notation on pointers. However, there are some things to know about. First is that an array's memory is at a fixed location- you can assign its address to a pointer, but cannot assign to its address (this is for much the same reason that x = 5 is legal, whereas 5 = x is not). Second is that true arrays (often called 'static arrays') allocate memory for the requested number of elements; hence, sizeof(array) is equal to the number of elements times sizeof(arrayElement); pointers, on the other hand, have a fixed size (often, but not always, the same as an int on the system in question). Last is that pointers need to be initialized before using them to access what they point at. Remember that variables in C and C++ are not initialized by default (except for those declared as static, or outside all functions), and pointers are no exception. Using an uninitialized pointer will at best yield garbage output, and at worst may do some serious damage (you're mucking with memory at essentially random locations), though many modern systems will terminate programs that try to access memory they don't own.

There are also other uses of pointers, such as 'returning' more than one value from a function (this was common in C, but isn't used as much in C++, thanks to 'reference variables'), allocating dynamic arrays (simply allocating a chunk of memory at runtime, and accessing it through the pointer, just as Polyphemus_ did in his example), and other things.

For more on pointers, you should see DaWei's article on them; the link is in his sig. It's worth the read, but if you don't understand them right away, that's normal. Pointers generally take a bit of work to understand, but once you do, you'll be amazed how easy they really are to use.

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nnxion

Nicely explained and nice to see you back pharoaoh (after 2 months).

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lectricpharaoh

Thanks. Been busy with school and RL, but decided to drop by. Good to see familiar faces along with some new ones.

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And once again, Probability proves itself willing to sneak into a back alley and service Drama as would a copper-piece harlot.
- Vaarsuvius, Order of the Stick