C – Array



    C Array is a collection of variables belongings to the same data type. You can store group of data of same data type in an array.

  • Array might be belonging to any of the data types
  • Array size must be a constant value.
  • Always, Contiguous (adjacent) memory locations are used to store array elements in memory.
  • It is a best practice to initialize an array to zero or null while declaring, if we don’t assign any values to array.

Example for C Arrays:

  • int a[10];       // integer array
  • char b[10];   // character array   i.e. string

Types of C arrays:

There are 2 types of C arrays. They are,

  1. One dimensional array
  2. Multi dimensional array
    1. Two dimensional array
    2. Three dimensional array, four dimensional array etc…

1. One dimensional array in C:

  • Syntax : data-type arr_name[array_size];
Array declaration
Array initialization
Accessing array
Syntax: data_type arr_name [arr_size]; data_type arr_name [arr_size]=(value1, value2, value3,….); arr_name[index];
int age [5]; int age[5]={0, 1, 2, 3, 4}; age[0];_/*0_is_accessed*/age[1];_/*1_is_accessed*/age[2];_/*2_is_accessed*/
char str[10]; char str[10]={‘H’,‘a’,‘i’}; (or)char str[0] = ‘H’;char str[1] = ‘a’; 

char str[2] = ‘i;

str[0];_/*H is accessed*/str[1];  /*a is accessed*/str[2];  /* i is accessed*/

Example program for one dimensional array in C:



value of arr[0] is 10
value of arr[1] is 20
value of arr[2] is 30
value of arr[3] is 40
value of arr[4] is 50

2. Two dimensional array in C:

  • Two dimensional array is nothing but array of array.
  • syntax : data_type array_name[num_of_rows][num_of_column]
Array declaration
Array initialization
Accessing array
1 Syntax: data_type arr_name [num_of_rows][num_of_column]; data_type arr_name[2][2] = {{0,0},{0,1},{1,0},{1,1}}; arr_name[index];
2 Example:int arr[2][2]; int arr[2][2] = {1,2, 3, 4}; arr [0] [0] = 1; arr [0] ]1] = 2;arr [1][0]  = 3; 

arr [1] [1] = 4;

Example program for two dimensional array in C:


value of arr[0] [0] is 10
value of arr[0] [1] is 20
value of arr[1] [0] is 30
value of arr[1] [1] is 40


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