An array consisting of two subscripts is known as a two-dimensional array. These are often known as an array of the array. In two-dimensional arrays, the array is divided into rows and columns. These are well suited to handle a table of data. In a 2-D array, we can declare an array as :

Declaration:-

Syntax: data_type array_name[row_size][column_size];

Ex:- int arr[3][3];

where the first index value shows the number of the rows and the second index value shows the number

of the columns in the array.

Initializing two-dimensional arrays:

Like the one-dimensional arrays, two-dimensional arrays may be initialized by following their declaration with a list of initial values enclosed in braces.

Ex: int a[2][3]={0,0,0,1,1,1}; initializes the elements of the first row to zero and the second row to one. The initialization is done row by row. 

above statement can also be written as

int a[2][3] = {{ 0,0,0},{1,1,1}};

by surrounding the elements of each row by braces.

We can also initialize a two-dimensional array in the form of a matrix as shown below

int a[2][3]={

{0,0,0},

{1,1,1}

};

When the array is completely initialized with all values, explicitly we need not specify the size of the first dimension.

Ex: int a[][3]={

{0,2,3},

{2,1,2}

};

If the values are missing in an initializer, they are automatically set to zero.

Ex: int a[2][3]={

{1,1},

{2}

};

Will initialize the first two elements of the first row to one, the first element of the second row to two, and all other elements to zero.