Two Dimensional Arrays in C

The two dimensional array is also called a matrix.in two dimensional array elements are stored by rows, so the rightmost subscript, or column, varies fastest as elements are accessed in storage order

Here is a sample program that stores roll number and marks obtained by a student side by side in a matrix

main( ) 
{ 
 int stud[4][2] ; 
 int i, j ; 
 for ( i = 0 ; i <= 3 ; i++ ) 
 { 
 printf ( "\n Enter roll no. and marks" ) ; 
 scanf ( "%d %d", &stud[i][0], &stud[i][1] ) ; 
 } 
 for ( i = 0 ; i <= 3 ; i++ ) 
 printf ( "\n%d %d", stud[i][0], stud[i][1] ) ; 
} 

The complete array arrangement is shown below

Initialising a 2-Dimensional Array

int stud[4][2] = {
{ 1234, 56 },
{ 1212, 33 },
{ 1434, 80 },
{ 1312, 78 }
} ;

It is important to remember that while initializing a 2-D array it is necessary to mention the second (column) dimension, whereas the first dimension (row) is optional

int arr[2][3] = { 12, 34, 23, 45, 56, 45 } ;
int arr[ ][3] = { 12, 34, 23, 45, 56, 45 } ;