What is a one-dimensional array in C language?

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

Syntax

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]

Initialization

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

• Compile time initialization
• Runtime initialization

Example

Following is the C program on compile time initialization −

 Live Demo

#include<stdio.h> 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]); }

Output

Upon execution, you will receive the following output −

Elements of the array are 10 20 30 40 50

Example

Following is the C program on runtime initialization −

 Live Demo

#include<stdio.h> 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]); }

Output

The output is as follows −

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

Note

• 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.

Example

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("
Array a:
");    for( i=0; i<4; i++ )       printf("arr[%d]: %d
",i,a[i]);       printf("
Array b:
");    for( i=0; i<4; i++)       printf("arr[%d]: %d
",i,b[i]);       printf("
Array c:
");    for( i=0; i<4; i++ )       printf("arr[%d]: %d
",i, c[i]);    return 0; }

Output

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