Array of Pointers in C Programming
Array of pointers
Syntax:
data-type *array-name[expression];
Where,
expression - is the number of elements to be taken in the array.
- The square bracket over here will take the precedence over the '*' operator.
- Each element in array-name will hold a pointer to the data-type.
Example : An array of pointers which stores a character of strings
#include <stdio.h>
void main ()
{
char *names[5] =
{
"Prajakta",
"Ravi",
"Jaya",
"Sapna",
"Prashant"
};
int i;
for ( i = 0; i < 5; i++)
{
printf("Value of names[%d] = %s\n", i, names[i] );
}
}
Value of names[0] = Prajakta
Value of names[1] = Ravi
Value of names[2] = Jaya
Value of names[3] = Sapna
Value of names[4] = Prashant
Dynamic Memory Allocation
- The memory that is allocated during run time is called as dynamic memory allocation.
- The memory in dynamic allocation is allocated and freed whenever it is required so that the space is not wasted.
- There are four routines which allow this type of function.
They are as follows:
1. malloc : It allocates the memory and returns a pointer to the first byte of the space that is allocated.
2. calloc : The space for an array of elements is allocated and is initialized to 0. Like malloc it also returns a pointer to the memory.
3. realloc : The size of the previous memory allocation is altered.
Example
Say if we have allocated 10 bytes to A by using malloc and we want to increase the memory by 5 bytes we would again use malloc. But if we use malloc the initial 10 bytes may get lost. In this case, we will use realloc which will add 5 bytes to the existing 10 bytes of A.
4. free : The memory which was allocated previously is freed.
