Define Dynamic memory allocation and there types?
Dynamic  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero allocation in c language enables the C  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero to allocate memory at runtime. Dynamic memory  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero in c language is possible by 4  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero of stdlib.h  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero file.
malloc(),  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero(), realloc(), and free().

Define malloc() function in C?
The malloc()  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero allocates single block of requested memory.
It doesn't  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero memory at execution time, so it has  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero value initially.
It returns NULL if memory is not  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero.
The  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero of malloc() function is given below:
ptr=(cast-type*) allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero(byte-size)

Define calloc() function in C ?
The  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero() function allocates multiple block of requested  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero.
It initially initialize all bytes to  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero.
It returns NULL if memory is not sufficient.
The syntax of calloc() function is given below:
ptr=( allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero-type*) allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero(number, byte-size)

Define realloc() function in C?
If  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero is not sufficient for  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero() or calloc(), you can reallocate the memory by  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero() function. In short, it changes the  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero size.
syntax of realloc() function.
ptr= allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero( allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero, new-size)

Define free() function in C ?
The  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero occupied by  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero() or calloc() functions must be released by  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero free() function. Otherwise, it will consume  allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero until program exit.
Syntax:
free( allocationcallingcalloccastfunctionfunctionsgarbageheaderinitializemallocmemoryprogrammerptrreallocsufficientsyntaxzero)