__1.Two-Dimensional Array__- Two dimensional array is also called a
**matrix.** - It is taken as an
**array of an array**. - Logically the 2 dimensional array 3 X 2 is taken as

1 2

3 4

5 6

Here there are 3 arrays. one array in each row - The values are stored in a
**row major form.**ie each row is stored first. The above array is stored as 1 2 3 4 5 6. - Each row array is represented as a[0],which consist of elements 1 and 2.a[1] consists of 3 and 4. and a[2] consists of 5 and 6
- Each element of a[0] is accessed as a[0][0] and a[0][1].Thus the value of a[0][0] is 1 and a[0][1] is 2.
- In memory whether it is a one dimensional or a two dimensional array the array elements are stored in one continuous chain.
- The
**size**of the array is**number of rows * number of columns**

__Initializing a 2-Dimensional Array:__- For initializing a 2-dimensional array we have to specify 2 dimensions. Number of rows and the Number of columns
- Ex1:

int emp[4][3]={

{1,100,'a'},

{2,100,'a'},

{3,98,'b'},

{4,90,'c'}

}; - Ex2: int emp[4][3]={1,100,'a',2,100,'a',3,98,'b',4,90,'c'};
- While initializing a 2-D array it is necessary to mention the second dimension ie the number of columns.The first dimension ie number of rows is optional.
- Ex: int a[2][3]={1,2,3,4,5,6}; is same as int a[][3]={1,2,3,4,5,6}; are same. But int a[2][]={1,2,3,4,5,6}; and int a[][]={1,2,3,4,5,6} are wrong way of initializing.
- In one dimensional arrays name[i] is same as *(name+i). Similarly in 2-dimensional array *(a[2]+1) is same as *(*(a+2)+1).This refer to the 2nd row 1st element.
- Thus a[2][1] is same as *(a[2]+1) and *(*(a+2)+1)

__Example: passing 2 dimensional array to a function__#include<stdio.h>

main()

{

**int**i,j,a[3][2];

**for**(i=0;i<3;i++)

{

**for**(j=0;j<2;j++)

{

a[i][j]=i;

}

}

printArr(a,3,2);

printArray(a,3,2);

**return**0;

}

**void**printArr(

**int**a[][2],

**int**m,

**int**n)

{

**int**i,j;

**for**(i=0;i<m;i++)

{

**for**(j=0;j<n;j++)

{

printf("a[%d][%d]=%d is in address=%8u\n",i,j,a[i][j],&a[i][j]);

}

}

}

**void**printArray(

**int**(*a)[2],

**int**m,

**int**n)

{

**int**i,j;

**int***p;

**for**(i=0;i<m;i++)

{

**for**(j=0;j<n;j++)

{

p=a+i;

printf("a[%d][%d]=%d is in address=%p\n",i,j,*(p+j),(p+j));

}

}

}

__Output__

a[0][0]=0 is in address=2609148672

a[0][1]=0 is in address=2609148676

a[1][0]=1 is in address=2609148680

a[1][1]=1 is in address=2609148684

a[2][0]=2 is in address=2609148688

a[2][1]=2 is in address=2609148692

a[0][0]=0 is in address=0x7fff9b847300

a[0][1]=0 is in address=0x7fff9b847304

a[1][0]=1 is in address=0x7fff9b847308

a[1][1]=1 is in address=0x7fff9b84730c

a[2][0]=2 is in address=0x7fff9b847310

a[2][1]=2 is in address=0x7fff9b847314

**2.Three-Dimensional Array:**- Each 3 dimensional array is taken as an array of two-dimensional array
- Eg: int a[2][3][4]; is a 3 dimensional array. This array consist of 2 arrays of the size 3 X 4. Each array is referred as a[0] & a[1]. Thus a[0] consist of 12 elements and a[1] also consists of 12 elements.
- The 3 X 4 two dimensional array is then taken as 3 arrays of the size 4.
- When passing a array to the function,we have to specify the inner dimensions.so while passing this 3 dimension array we have to pass 3 and 4 as inner dimension.
- The following 2 expressions refer to the same element in the 3 dimensional array

- a[1][2][3]
- *(*(*(arr+1)+2)+3)

__Example Program:__#include<stdio.h>

main()

{

**int**i,j,k,x=0,a[2][3][4];

**for**(i=0;i<2;i++)

{

**for**(j=0;j<3;j++)

{

**for**(k=0;k<4;k++)

{

a[i][j][k]=x;

x++;

}

}

}

printArr(a,2,3,4);

**return**0;

}

**void**printArr(

**int**a[][3][4],

**int**m,

**int**n,

**int**p)

{

**int**i,j,k;

**for**(i=0;i<m;i++)

{

**for**(j=0;j<n;j++)

{

**for**(k=0;k<p;k++)

{

printf("a[%d][%d][%d}=%d is in address=%8u\n",i,j,k,a[i][j][k],&a[i][j][k]);

}

}

}

}

Output

a[0][0][0}=0 is in address=544671328

a[0][0][1}=1 is in address=544671332

a[0][0][2}=2 is in address=544671336

a[0][0][3}=3 is in address=544671340

a[0][1][0}=4 is in address=544671344

a[0][1][1}=5 is in address=544671348

a[0][1][2}=6 is in address=544671352

a[0][1][3}=7 is in address=544671356

a[0][2][0}=8 is in address=544671360

a[0][2][1}=9 is in address=544671364

a[0][2][2}=10 is in address=544671368

a[0][2][3}=11 is in address=544671372

a[1][0][0}=12 is in address=544671376

a[1][0][1}=13 is in address=544671380

a[1][0][2}=14 is in address=544671384

a[1][0][3}=15 is in address=544671388

a[1][1][0}=16 is in address=544671392

a[1][1][1}=17 is in address=544671396

a[1][1][2}=18 is in address=544671400

a[1][1][3}=19 is in address=544671404

a[1][2][0}=20 is in address=544671408

a[1][2][1}=21 is in address=544671412

a[1][2][2}=22 is in address=544671416

a[1][2][3}=23 is in address=544671420

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