Pointer Arithmetic

·         Pointer is a variable that points to a memory location.

·         Memory addresses are numeric value that ranges from zero to maximum memory size in bytes.

·         These addresses can be manipulated like simple variables.

·         Increment, decrement, calculate or compare these addresses manually can be done.

·         C language provides a set of operators to perform arithmetic and comparison of memory addresses.

·         Pointer arithmetic and comparison in C is supported by following operators -

Ø  Increment and decrement ++ and --

Ø  Addition and Subtraction + and -

Ø  Comparison <, >, <=, >=, ==, !=

Pointer Increment and Decrement

·         Increment operator when used with a pointer variable returns next address pointed by the pointer.

·         The next address returned is the sum of current pointed address and size of pointer data type.

·         For example, consider the below statements.

int num = 5;   // Suppose address of num = 0x1230

int *ptr;      // Pointer variable

ptr = #    // ptr points to 0x1230 or ptr points to num

ptr++;         // ptr now points to 0x1234, since integer size is 4 bytes

ptr--;         // ptr now points to 0x1230