Tag Archives: C 2D array

C 1D,2D Array

Array is data structure in C . They are defined at compile time. Used to store same kind of information in sequential manner. Contiguous memory is allocated for array.

If we want to store marks of 100 students. Instead of declaring 100 float variables like (float marks1,marks2, …. ,marks100) we can declare one variable marks[100];

Caution: array starts from 0;

so information can be stored in marks[0]. marks[1], .. . . . , marks[99].

How to declare an array ?

data_type   identifier[ size_of_array];


int a[100];

float b[30];

char c[50];


How to initialize an array at the time of declaration ?

int a[5]={1,2,3,4,5};

value of a[0] is 1;

value of a[1] is 2;

similarly value of a[4] is 5;

a[5] is not accessible because we have declare array as int a[5] which consist of 5 variables from a[0] to a[4].


Accessing element in array :

float arr[6];

we can access 5 th element in array by arr[4] .


Types of Array :

  • 1D Array
  • 2D Array
  • Multidimensional array.

1-D Array :

Declaration :

int arr[10];

Element access :

eq. 2nd element


2-D Array :

Declaration :

int arr[5][5];

the above declaration will create 5 X 5 array with name arr.

Element access:

To access 2nd element in row and 3rd element in column we can access by a[1][2];


=>similarly we can apply rule in multidimensional array.


1-D Array

To declare an array of size 5 ,input the value from user printing the same.

2-D Array 

Declare a 2-D array of size 3X3 and store below matrix and print.

1 2 3

4 5 6

7 8 9


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