Accessing the Address of a variable

Introduction Generations of Computers Classification of Computers Basic Anatomy of a Computer System Memory Management Computer Software Operating System

Algorithm Flowcharts

Programming Language Generations of Programming Languages Introduction to C Structure of C Programming Language Integrated Development Environment First C program, Hello World Executing a C Program Constants in C Variables in C C Storage Classes and Storage Class Specifiers

Introduction Arithmetic operators Relational Operators Logical Operators Assignment Operator Increment and Decrement Operators Conditional Operators Bitwise Operators Precedence and Associativity

Control Instructions in C if Statement in C if-else Statement Nested if-else statement else if ladder Switch Statements in C

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Pointers in C Accessing the Address of a variable Pointer Operations

Dynamic Memory Allocation

Pointer is a variable. It is used to store the address of any other variable. To be more specific, an integer pointer points to an integer variable, a character pointer points to a character variable. In general, a pointer of specific type points to a variable of the same type. All pointers take only 2 bytes.

Because the actual position of a variable in memory is system-dependent, we don't know the address of a variable right away. So, how can we figure out what a variable's address is? This may be done using the & operator and is available in C. We have already seen the use of this address operator in the scanf function. The & operator immediately preceding a variable returns the address of the variable associated with it.

For example:

p = &myname;

would assign the address 12345 (Location of the variable) to the variable p. The & operator can be recalled as 'address of'. The & operator can be used only with a simple variable or an array element.

The following are illegal use of (&) address operator:

1: &125 (pointing at constants).

2: int y[10];

&y (pointing at array names).

3: &(x+y) (pointing at expressions). If x is an array, then expressions such as &x[0] and &x[i+3]

Fundamentals of the Computer System

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Operators in C

Conditional Branching

Iteration and Loops

Array in C

Functions in C

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Strings

Structures and Union

Pointers in C

File Handling in C

Advanced

Accessing the Address of a Variable

For example:

The following are illegal use of (&) address operator: