Arrays in C

An array is a collection of similar types of data element which holds fixed number of values.

Example:
For example an int array holds the elements of int types while a float array holds the elements of float types
Advantages:
Less code is required to access the data
We can access any element randomly using the array
We can sort the elements of array
Disadvantage:
Array size is fixed so we cannot change the value
Types:
There are 2 types of C arrays.They are

1)    One dimensional array
2)    Multi dimensional array

One dimensional array

 Syntax:

 Data_type  array_name [array_Size];

 Example

  int marks[10];  

 Where int is the data_type, marks is the array_name and 10 is the array_size.

 Note: 
Array index is always started from 0.Its range  between 0 to n-1.
Where n is the number of elements.0 is the lower index and n-1 is the upper index.
The size and type of arrays cannot be changed after its declaration.

Declaration with Initialization

There are two ways to declare with initialize the array. They are

1^ST Way:

      int marks[5];//declaration of array       

      marks[0]=10;//initialization of array    

      marks[1]=20;    

      marks[2]=30;    

      marks[3]=40;    

      marks[4]=50;  

 2^nd Way

 We can initialize the array at the time of declaration like

  int marks[5]={10,20,30,40,50};

  or  

   int marks[]={20,30,40,50,60};  

Example:

   #include<stdio.h>  

   #include<conio.h>

    void main(){    

     int i=0;    

     clrscr();

    int marks[5]={10,20,30,40,50};//declaration and initialization of array    

    

     for(i=0;i<5;i++){      

     printf("%d \n",marks[i]);    

        }  

   getch();

       }    

   Output:

     10

20

30

40

50

How to take 1D Array values from user in C

#include <stdio.h>

#include<conio.h>

 void  main()

 {

    int marks[20], i, n;

   clrscr();

     printf("Enter n:\n ");

     scanf("%d", &n);

      for(i=0; i<n; ++i)       //Input statement

     {

         printf("Enter number%d: ",i+1);

         scanf("%d", &marks[i]);

        }

    

for(i=0; i<n; ++i)      // Output statement

     {

       printf("Array is:%d\n", marks[i]);

       }

getch();

}

Example 2: Calculate average marks using array in C

#include <stdio.h>

#include <conio.h>

void main()

{

     int marks[10], i, n, sum = 0, average;

     clrscr()

     printf("Enter n: ");

     scanf("%d", &n);

     for(i=0; i<n; ++i)

     {

          printf("Enter number%d: ",i+1);

          scanf("%d", &marks[i]);

          sum += marks[i];

     }

     average = sum/n;

   printf("Average = %d", average);

  getch();

}
Two Dimensional Array
Two dimensional array is know as matrix because it is represented by rows and columns.Two ,three or other dimensional arrays are also known as multidimensional arrays.
Declaration of 2D Array:
data_type  array_name[row][column];
Example:

 int arr[2][3];  
Where 2 is the row number and 3 is the column number.

 Initialization of 2D Array

int arr[2][3]={{1,2,3},{2,3,4}};

Example:

#include<stdio.h> 

#include<stdio.h> 

void main(){     

int i,j;  

clrscr();

int arr[2][3]={{1,2,3},{2,3,4}};    

  

for(i=0;i<2;i++){   

 for(j=0;j<3;j++){   

   printf("%d\t",arr[i][j]);   

 } 

 printf("\n");

} 

 getch();

}  

  Output:

     1 2 3

     3 4 5

How to take 2D Array values from user in C

#include<stdio.h>

#include<conio.h>

void  main()

{

    int arr[2][3];

    int i, j;

  clrscr();

    printf("Enter array element \n");

    for(i = 0; i < 2;i++)

    {

        for(j = 0; j < 3; j++)

        {

            scanf("%d", &arr[i][j]);

        }

    }

    for(i = 0; i < 2; i++)

    {

        for(j = 0; j < 3; j++)

        {

            printf("%d\t", arr[i][j]);

        }

       

        printf("\n");

    }

getch();

}