C – Pointer
- C Pointer is a variable that stores/points the address of the another variable.
- C Pointer is used to allocate memory dynamically i.e. at run time.
- The variable might be any of the data type such as int, float, char, double, short etc.
Syntax : data_type *var_name;
Example : int *p; char *p;
- Where, * is used to denote that “p” is pointer variable and not a normal variable.
Key points to remember about pointers in C:
- Normal variable stores the value whereas pointer variable stores the address of the variable.
- The content of the C pointer always be a whole number i.e. address.
- Always C pointer is initialized to null, i.e. int *p = null.
- The value of null pointer is 0.
- & symbol is used to get the address of the variable.
- * symbol is used to get the value of the variable that the pointer is pointing to.
- If pointer is assigned to NULL, it means it is pointing to nothing.
- Two pointers can be subtracted to know how many elements are available between these two pointers.
- But, Pointer addition, multiplication, division are not allowed.
- The size of any pointer is 2 byte (for 16 bit compiler).
Example program for pointer in C:
int *ptr, q;
q = 50;
/* address of q is assigned to ptr */
ptr = &q;
/* display q's value using ptr variable */