What is a one-dimensional array in C language?

CServer Side ProgrammingProgramming

An array is a group of related items that store with a common name.


The syntax is as follows for declaring an array −

datatype array_name [size];

Types of arrays

Arrays are broadly classified into three types. They are as follows −

  • One – dimensional arrays
  • Two – dimensional arrays
  • Multi – dimensional arrays

One – dimensional array

The Syntax is as follows −

datatype array name [size]

For example, int a[5]


An array can be initialized in two ways, which are as follows −

  • Compile time initialization
  • Runtime initialization


Following is the C program on compile time initialization −

 Live Demo

int main ( ){
   int a[5] = {10,20,30,40,50};
   int i;
   printf ("elements of the array are");
   for ( i=0; i<5; i++)
      printf ("%d", a[i]);


Upon execution, you will receive the following output −

Elements of the array are
10 20 30 40 50


Following is the C program on runtime initialization

 Live Demo

main ( ){
   int a[5],i;
   printf ("enter 5 elements");
   for ( i=0; i<5; i++)
      scanf("%d", &a[i]);
   printf("elements of the array are");
   for (i=0; i<5; i++)
      printf("%d", a[i]);


The output is as follows −

enter 5 elements 10 20 30 40 50
elements of the array are : 10 20 30 40 50


  • The output of compile time initialised program will not change during different runs of the program.

  • The output of run time initialised program will change for different runs because, user is given a chance of accepting different values during execution.


Following is another C program for one dimensional array −

 Live Demo

#include <stdio.h>
int main(void){
   int a[4];
   int b[4] = {1};
   int c[4] = {1,2,3,4};
   int i; //for loop counter
   //printing all elements of all arrays
   printf("\nArray a:\n");
   for( i=0; i<4; i++ )
      printf("arr[%d]: %d\n",i,a[i]);
      printf("\nArray b:\n");
   for( i=0; i<4; i++)
      printf("arr[%d]: %d\n",i,b[i]);
      printf("\nArray c:\n");
   for( i=0; i<4; i++ )
      printf("arr[%d]: %d\n",i, c[i]);
   return 0;


The output is stated below −

Array a:
arr[0]: 8
arr[1]: 0
arr[2]: 54
arr[3]: 0
Array b:
arr[0]: 1
arr[1]: 0
arr[2]: 0
arr[3]: 0
Array c:
arr[0]: 1
arr[1]: 2
arr[2]: 3
arr[3]: 4
Updated on 15-Mar-2021 15:06:17