C Programming One Dimensional Array with Examples

One dimensional array in c programming; Through this tutorial, you will learn about One Dimensional Array in C with the help of examples.

One Dimensional Array in C with Examples

• 1 D Array Definition in C
• Rules For Declaring One Dimensional Array
• 1 D Array Declaration in C
• 1 D Initialization of C Array
• 1 D Access Array Elements in C
• Example 1 – One Dimensional Array in C
• Example 2 – Program to print the largest and second largest element of the array in c

1 D Array Definition in C

One Deminsional 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.

Rules For Declaring One Dimensional Array

• An array variable must be declared before being used in a program.
• The declaration must have a data type(int, float, char, double, etc.), variable name, and subscript.
• The subscript represents the size of the array. If the size is declared as 10, programmers can store 10 elements.
• An array index always starts from 0. For example, if an array variable is declared as s[10], then it ranges from 0 to 9.
• Each array element stored in a separate memory location.

1 D Array Declaration in C

You can use the following 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.

1 D 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;  

You can also initialize an array like this.

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

1 D 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 – 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<5;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

Example 2 – 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