Pointers are the one of the best feature of C language.They are a powerful tool and handy to use once they are mastered. There are a number of reasons for using pointers.
- A pointer enables us to access that is defined outside the function.
- Poniters are more efficient in handling the data tables.
- Pointers reduse the length and complexity of a program.
- They increase the execution speed.
- The use of a pointer array to character strings result in saving of data storage space in memory.
What are Pointers? pointer is a variable whose value is the address of another variable, i.e., direct address of the memory location. Like any variable or constant, you must declare a pointer before using it to store any variable address. The general form of a pointer variable declaration is −
Type is the pointer's base type; it must be a valid C data type and var-name is the name of the pointer variable. The asterisk * used to declare a pointer is the same asterisk used for multiplication. However, in this statement the asterisk is being used to designate a variable as a pointer. Take a look at some of the valid pointer declarations − /* pointer to an integer */double *dp; /* pointer to a double */
/* pointer to a float */char *ch /* pointer to a character */The actual data type of the value of all pointers, whether integer, float, character, or otherwise, is the same, a long hexadecimal number that represents a memory address. The only difference between pointers of different data types is the data type of the variable or constant that the pointer points to.
How to Use Pointers?
There are a few important operations, which we will do with the help of pointers very frequently.
(a) We define a pointer variable,
(b) assign the address of a variable to a pointer and
(c) finally access the value at the address available in the pointer variable. This is done by using unary operator * that returns the value of the variable located at the address specified by its operand. The following example makes use of these operations −