## Pointer Use In Array

pointer has a very close relationship with the array. we will see it’s application with the linear and multidimensional array.

#### Pointer Application with One Dimensional Array

An array name represents the base address of itself.

##### Difference between arr_num and &arr_num

Run the Program –

##### An increment in Array Pointer

Pointer takes the advantage of array’s continuous storage feature. We can access every element through a single pointer variable by stepping continuous memory locations.

Pre-requisite: Must be aware of Use of Indirection operator.

###### An increment in character array pointer:

We can see every element is stored in 1-byte space because this array has char datatype and char datatype need only 1-byte storage.

— A char pointer will jump 1 byte in a single increment.See the below example –

Explanation

For i=0  :  *(ptr_name+i) = *(name+0)= *(&name+0) =*(0028FF14+0)=*(0x0028FF14)=10

For i=1  :  *(ptr_name+1) = *(name+1)= *(&name+1) =*(0028FF14+1)=*(0x0028FF15)=20

###### An increment in integer array pointer

Let us take an integer array –

unsigned int arr_num = {10,20,30,40,50};

Memory assignment of above array is like this –

let us see addresses through a program-

Output:

Explanation

For i=0  :  *(ptr_arr+i) = *(arr_num+0)= *(&arr_num+0) =*(0028FF04+0)=

*(0x0028FF04)=10

For i=1  :  *(ptr_arr+1) = *(arr_num+1)= *(&arr_num+1) =*(0028FF04+1)=

*(0x0028FF08)=20

For i=2  :  *(ptr_arr+2) = *(arr_num+2)= *(&arr_num+2) =*(0028FF04+2)=

*(0x0028FF0C)=30.

Remember:

• char pointer jumps only 1 byte in single increment whatever the processor size is.
• int pointer jumps only 4 byte in single increment if processor is 32 bit.
• float pointer jumps only 4 byte in single increment if processor is 32 bit.
• double pointer jumps only 8 byte in single increment if processor is 32 bit.

#### Pointer Application with Two Dimensional Array

Although a two-dimensional array has multiple rows yet its memory map is linear as the one-dimensional array.see the below diagram –

##### 2-D Matrix/Array Memory Diagram

So in above diagram, you can see that in memory stores same as the 1-D array so you can access every element through a single pointer as we do in the one-dimensional array.

##### Points To remember for two-dimensional array pointer

E.g. unsigned int arr[]={10,20,30,40,50,60};

arr=&arr= represents the base address of 1-D array block1.

&arr= represents the address of 0th row and 0th coloumn.

&arr = represent the base address of complete Matrix.

See the below diagram to understand the physical meaning of arr,&arr,&arr,&arr.

##### Program

Program to show the addresses of arr,&arr,&arr,&arr and increment behaviour.

Output:

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