Array in C

 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

• Two dimensional array
• Three dimensional array, four dimensional array etc…

1. One dimensional array in C:

• Syntax : data-type arr_name[array_size];

Example program for one dimensional array in C:

#include<stdio.h>
int main()
{
    int i;
    int arr[5] = {10,20,30,40,50};  
    // declaring and Initializing array in C
    //To initialize all array elements to 0, use int arr[5]={0};
    /* Above array can be initialized as below also
       arr[0] = 10;
       arr[1] = 20;
       arr[2] = 30;
       arr[3] = 40;
       arr[4] = 50;
    */
    for (i=0;i
    {
        // Accessing each variable
        printf("value of arr[%d] is %d \n", i, arr[i]);
    }
}

Output:

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]

Example program for two dimensional array in C:

#include<stdio.h>
int main()
{
    int i,j;
    // declaring and Initializing array
    int arr[2][2] = {10,20,30,40};
    /* Above array can be initialized as below also
       arr[0][0] = 10;   // Initializing array
       arr[0][1] = 20;
       arr[1][0] = 30;
       arr[1][1] = 40;
    */
    for (i=0;i
    {
       for (j=0;j
       {
          // Accessing variables
          printf("value of arr[%d] [%d] : %d\n",i,j,arr[i][j]);
       }
    }
}

Output:

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