Pointers in C Programming

• Before going to start pointers. Let’s recall the concepts of variables, Variable is a memory location and every memory location has an address that can be accesses through the ampersand(&) operator.
  
• Let us consider an example for a clear understanding of variables and their addresses.

    Program:

   Output:

Pointers:

A pointer is a variable that stores the address of another variable. To use the function of pointers in C language we must understand the two unary operators

1. Unary operator &(ampersand) to returns the address of that variable

1.  Unary operator *(asterisk) is used for two things-Used to declare the pointer variable and used to access the value stored in the variable

Declaration of pointer:

Type *var_name;
Here type is pointers base type i.e it must be valid c data type and var_name is the name of the pointer variable. *(Asterisk) is used to declare the pointer variable. Here is some of the various pointer variable declarations
int *ip;
double *dp;
float *fp;
char *cp;
There are mainly three steps involved to use the pointers effectively

1. Declare the pointer variable
2. Assign the address of the variable to a pointer variable
3. Access the value

Sample Program:

Output:

Pointers to array:-

int shsArray[10];

int *ptr = &shsArray;

In the below example array pointer ptr stores the address of the shsArray

Example :

Output :

Null Pointer:-

• If the pointer is declared as NULL then it is called a null pointer. If the programmer has no value of pointer at the time of declaration then the pointer is assigned by a NULL value. It gives a better approach to solve problems.

Program :

Output :

Advantages of the pointers:-

• Pointers reduce the code.
• Pointers increase the performance of the code.
• Pointers are used in arrays, structures, and functions.
• Pointers are used to return the multiple values from the functions.
• Dynamic memory allocation is possible in pointers using malloc() and calloc() functions.

Here is an example to clearly understand the working of the pointers in a c programming language. The problem statement is swapping of the two numbers using pointers

Program :

Output :

Note: More examples will be covered in Problems on C page

Similarly you can also learn the structures, arrays and unions concepts in C programming Language.

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