Pointer Basics,Constant Pointers & Pointer to Constant.

Pointer Basics,Constant Pointers & Pointer to Constant.

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  BIRLA INSTITUTE OF TECHNOLOGY TOPIC:- POINTERS BASICS, CONSTANT POINTERS AND POINTERS TO CONSTANT DIVYANSH PARMARTHI MCA/25016/18 SHRADDHA
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  POINTERS • A pointeris a variable that points a address of a variable. • A pointer is declared using the * operator before an identifier.
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   Declaration ofPointer variables : type *pointer_name; where type is the type of data pointed to For example :- int *numberPointer;
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  ADDRESS (&) OPERATOR Pointer address operator is denoted by ‘&’ symbol  The & is a unary operator that returns the memory address of its operand. Example : &n - It gives an address on variable n
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  DEREFERENCING OPERATOR (*) We can access to the value stored in the variable pointed to by using the dereferencing operator (*) Syntax: *PointerVariable Example: int V = 101; int *P = &V;
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  POINTERS TO POINTERS A pointer to a pointer is a chain of pointers.  In pointer to a pointer, the first pointer contains the address of the second pointer, which points to the location that contains the actual value. Pointer Pointer Variable Address Address Value
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  Declaration of pointerto a pointer : int **ptr; For example : // local declaration int a; int *p; int **q; // Statment a=58; p=&a; q=&p;
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  cout << a<< “ “ <<endl; cout << *p << “ “ <<endl; cout<< **q << “ “ <<endl; OUTPUT 58 58 58
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  POINTERS AS PARAMETERS To make changes to a variable that exist after a function ends, we pass the address of the variable to the function For example : #include<iostream.h> void Indirectswap(char *ptr1, char *ptr2) { char c = *ptr1; *ptr1 = *ptr2; *ptr2 = c; }
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  int main() { char a= ‘y’; char b = ‘n’; Indirectswap(&a,&b); cout<< a << “and”<< b << endl; return 0; } OUTPUT n and y
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  CONSTANT POINTERS AND POINTERSTO CONSTANT BY :- SHRADDHA MALVIYA
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  Constant pointer  Constantpointer cannot be modified.  Modification in integer to which it points to it is allowed.  Syntax: int n1=20; int *const ptr=&n1; //Declare constant
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  Example of constantpointer
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  Output
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  Pointer to constant Pointer to constant object is called as pointer to constant object. Syntax: int n=30; const int *ptr=&n; “const int” means integer constant. We cannot change value of integer. We can change address of such pointer so that it will point to new memory allocation
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  Example of pointerto constant
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  Output
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  Difference Constant pointer Pointerto constant Pointer can be incremented. Pointer is not incremented. Constant pointer is pointing to data object. Pointer is pointing to constant data object.t Declaration :int * const ptr; Declaration: const int *ptr;
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  THANK YOU