Arrays in C Programming with examples

C programming array; In this tutorial, i am going to show you what is array in c programming and how to use array in c.

Arrays in C programming

Here, i will show you how to declare, initialize, access, and delete elements of an array in c programming with the help of examples:

  • Array Definition in C
  • Array Declaration in C
  • Initialization of C Array
  • Access Array Elements in C
  • Example 1 – Program to print the largest and second largest element of the array in c
  • Example 2 – Program to find smallest and second smallest element in an array in c

Array Definition in C

An array is a variable that can hold multiple values or similar types of data. For example; an int array store the elements of int data type and a float array holds the elements of float data type, so on.

Note that:- An arrays can store the primitive type of data such as int, char, double, float. Arrays are the derived data type in C programming language which can store the primitive type of data such as int, char, double, float

Array Declaration in C

The syntax to declare an array in the c programming language; as shown below:

data_type array_name[array_size];  

Let’s see the following example for how to declare array in c programming; as shown below:

float mark[5];

Here, Mark is a float data type. It means it hold float types of value in it. And its size is 5.

Initialization of C Array

To initialize an array in c by using the index of each element. See the following easy way to initialize array in c programming; as shown below:

marks[0]=80;//initialization of array  
marks[1]=60;  
marks[2]=70;  
marks[3]=85;  
marks[4]=75;  

Initialize an array like this:

int mark[] = {19, 10, 8, 17, 9};

Access Array Elements in C

Using array index, you can easily access any element stored in c array; as shown below: 

Let, you have declared an array named mark as above. So, you can access the element values in array by using array index; as shown below:

mark[0] /* first element of array mark*/
mark[4] /* last (4th) element of array mark*/

Example 1 – Program to print the largest and second largest element of the array in c

Use the following steps to write program to print largest and second largest element of the array in c:

  • Initialize and declare array size variable
  • Then initialize and declare the largest and second largest variable
  • Take array size or length from user in program
  • Take array elements or items input from the user in program
  • Define logic inside loop to find the largest and second largest elements from array
  • At the last, print largest and second largest elements from array in c
#include <stdio.h>
#include <stdlib.h>
int main()
{
int size,i,arr[50];//variable declaration for size of array
int large=0, secondLarge=0;
printf("Enter the size of array: ");
scanf("%d",&size);//taking input from user for number of elements in array
for(i=0; i<size; i++){
    
    printf("\n Enter the array element ");
    printf("%d :",(i+1));
    
    scanf("%d",&arr[i]);//Taking input for array elements 
    if(large<arr[i]){
      secondLarge=large;
      large=arr[i];
    }
    else if(secondLarge<arr[i]){
    secondLarge=arr[i];
    }
}
//display result on the screen
printf("\n\n\n");
printf("The largest number in array is %d",large);
printf("\n The second largest number in array is %d",secondLarge);
return 0;
}

Output of the above c program; as shown below:

Enter the size of array: 5
Enter the array element 1 :321
Enter the array element 2 :123
Enter the array element 3 :654
Enter the array element 4 :456
Enter the array element 5 :987
The largest number in array is 987
The second largest number in array is 654

Example 2 – Program to find smallest and second smallest element in an array in c

Use the following steps to write program to print smallest and second smallest element of the array in c:

  • Initialize and declare array size variable
  • Then initialize and declare the smallest and second smallest variable
  • Take array size or length from user in program
  • Using for loop; take array elements or items input from the user in program
  • Implement loop and define logic inside loop to find the smallest and second smallest elements from array
  • At the last, print smallest and second smallest elements from array in c
#include <stdio.h>
#include <string.h>
void main()
{
 int smallest, secondsmallest;
 int array[100], size, i;
 
 printf("\n How many elements do you want to enter: ");
 
 scanf("%d", &size);
 for(i=0; i<size; i++){
    
    printf("\n Enter the array element ");
    printf("%d :",(i+1));
    
    scanf("%d",&array[i]);//Taking input for array elements 
}
 
 for (i = 0 ; i < size; i++){
	 if (array[0] < array[1]) {
		 smallest = array[0];
		 secondsmallest = array[1];
	 }
	 else {
		 smallest = array[1];
		 secondsmallest = array[0];
	 }
	 for (i = 2; i < size; i++) {
		 if (array[i] < smallest) {
			 secondsmallest = smallest;
			 smallest = array[i];
		 }
		 else if (smallest == secondsmallest){
			 smallest = secondsmallest;
			 secondsmallest = array[i];
		 }
			 else if (array[i] < secondsmallest && array[i] > smallest) {
			 secondsmallest = array[i];
		  }
	 }
 }
 printf(" \nSecond smallest element is %d", secondsmallest);
 printf(" \nSmallest element is %d\n", smallest);
}

Output of the above c program; as shown below:

How many elements do you want to enter: 5
Enter the array element 1 :2
Enter the array element 2 :6
Enter the array element 3 :4
Enter the array element 4 :8
Enter the array element 5 :5
Second smallest element is 4 
Smallest element is 2

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