Pointer

Pointer

 Pointer is derived data type in C. Pointer contain memory address as there value. Since these memory address are the location in the Computer memory where program instruction and data our Store.

 Pointer variable is used to hold memory address. This address is the location of the another variable  where it have been store in the memory.

  In other words we can say that pointer is  a variable which hold the address of another variable is declared as first variable pointing to the second variable.

Operator used with pointer:-

there are two basic operators used with pointers.

a) Address Pointer (&):-

 the address pointer give the address of variable.

b) Indirection Operator: -

 Indirection operator gives the value of the variable that the pointer is pointing to variable of program.

Ex.- int *p;

     int q;

  r = &q;

pointer arithmetic: -

 the pointer arithmetic refers to the use of the pointer with variable arithmetic operators. In C pointers can be used along with arithmetic operation like addition, subtraction, increment or decrement.

Pointers and functions:-

pointers are mainly used alone with function for passing the address of the argument generally an argument can be passed onto the function in two ways.

(i) call by Value

(ii) call by reference

1- call by Value:-

 Call by Value refer to sending value or argument on to the function. In this method the value of actually argument is copied on to the corresponding format argument whenever a function is called the various operation performed wonder effect on the wedding actual argument in the main() function.

2- call by reference: -

 Call by reference is a method used to accept any function through the main program using pointers.

 Using this method the operation performed affect the value of actual argument. This age because the argument contain the address of actual argument so any change on that address affect the value.