#constant pointers

Pointers are generally the most feared part in a programming language. The only concept which many programmers doesnt seem to get. Well just get over the fact that pointers are somrthing terrifying build only to make prgrammers like us have horrifying nighmares....!! Heres the truth about pointers....!! POINTERS ARE NOTHING MORE THAN A VARIABLE...!! but the twist here is that they are a special kind of variables that stores special kind of info and that special info is the ADDRESS of another variable. See just like an int variable can store only int values and a float can store only float values, same is the case with the pointers. An int pointer stores the address of an integer variable only and not a float variable. So in 1 line a pointer is : SIMPLY A VRAIABLE THAT STORES ADDRESSES OF ANOTHER VARIABLE OF SAME DATA TYPE. DEFINING A POINTER defining a pointer is a little different than defining variables. int* x; /*we just declared an integer pointer which means that it vil only store addresses of integer variables.*/ dont be confused with the star (*)...u can also do lyk int *x or int * x...its all d same....!! Similarly to create a float or a char pointer just change the data type float* x; char* x; now store something in the pointer. REMEMBER : The variable that the pointer is pointing to is called a "POINTEE". int pointee; int* pointer; pointer = &pointee; //Now wat the hell is "&" for.. >:) this is known as "address of" operator it takes a variable and returns its address. for eg: &pointee will give you the address of pointee, remember that pointers only store addresses so if we want pointer to point to pointee we will give the address of pointee So pointer is pointing to pointee now so wat.....?? Now we can access pointee through a dereference operater(*)... int pointee = 10; int* pointer; like cout<<*pointer; vil give 10. Suppose address of pointee is 1000 and value is 10. So pointer vil store 1000 as its value and when *pointer is done, it will go to the address conatined by pointer which is 1000 as of now and vill access d value storesd at that address. So *pointer is now the same as pointee. doing *pointer = 20; or pointee = 20 //is the same thing Suppose there is another int pointer  int* another_pointer ; now we want this new pointer to point to the same location that pointer is pointing to. so we vil do lyk: another_pointer = pointer; //another pointer vil now also point to pointee; So now the final programme to illustrate the concepts: int main() { int pointee = 10; int *pointer1, *pointer2; //u cant do lyk int* pointer1,pointer2,here pointer2 vil be pointer1 = &pointee; //a simple int cout< cout<<*pointer1; //value of pointee i.e 10 pointer2 = pointer1; //pointer2 now points also points to pointee  *pointer2 = 20; //value of pointee chngd to 20 cout< cout< cout<<*pointer2; //value of pointee which is now 20 cout<<*pointer1; //value os pointee which is now 20 I hope this vil settle all the dust about baiscs of POINTERS and now we can start understandin the intricate details about pointers and their GOTCAHS....!! This is just a very breif intro to POINTERS and Theres still a lot to learn about pointers so keep writing code and experimenting....!!

ARRAYS----> From bookish point of view...an array is a collection of homogeneous data, by homogeneous we mean dat the data vil be of same data type,may it be int or char or float. int arr[10]..is an array of data type integer with 10 variables occupying size of 40 bytes. Dis vil be same as defining int a0,a1,a.....a9 But the difference is dat v can now access dem easily through 1 name. for eg: if v want to access 2nd element we will do like arr[1] ,5th element arr[4] and so on. Remember: array-name[index] array-name can be anythng and index starts from 0 and not 1. an array of 5 elements: int arr[5] defining simple variables : arr1 arr2 arr3 arr4 arr5 using array arr[0] arr[1] arr[2] arr[3] arr[4] notice the indices Hope u get it..!! You can treat them just like normal variables but accessing them through array style. Remember: Arrays are allocated in memory contiguously. for eg: in ram arr[0],arr[1],arr[2] will be adjuacent to each other like address of arr[0] is 1000,address[1] is 1004 and so on...!! Now internally arrays are nothing more than "CONSTANT POINTERS". For eg: u declare int arr[10]; then arr is only the address of arr[0] and it vil always point to that location only For eg : int arr[5]; lets assume arr is pointing to 1000 So what happens when u require arr[3]. arr + index*sizeof(datatype) this formula is used 1000 + 3*4 //sizeof(int) is 4 which gives 1012 this vil be the address of arr[3]. Remember when i told u that arrays are allocated contigously in memory.This is the main importance . if they are not allocated contiguously then this scheme would fail. Since the compiler just multiplies d index with the size of data type and adds it to base address...u vil be surprised to knw that u can also use array like 3[arr]..this vil be same as arr[3]. and remember that arrays are like constant pointers internally you cannot assign an array to another variable once its been defined. and due to the way that arrays are implemented internally they hav O(c) access time.. which means constant access time. for further experience actually code the arrays for first hand experience.