Array
Array
Array is a collection of data elements, all of same data type, accessed using a common name. Array elements are placed in contiguous memory location. Array is one type of data structure that can store a fixed-size sequential collection of items of the same type. An array is a variable that can store multiple values. Array is the collection of homogeneous data elements.
Declaration:
To declare array in C, a programmer specifies the data type of items, array name and numbers of
items
required by an array as follows -
One dimensional array:
type arrayname[arraysize];
This is single-dimentional array. Array size must be positive integer.
Two dimensional array:
type arrayname[i][j];
here: i= numbers of rows and j= numbers of columns
This is called 2-Dimentional array. 2D array represent matrices.
Example:
- int a[5];
- int a[3][2];
Types of array:
In C programming language, there is two type of array-
- One dimentional(1-D) Array
- Two dimentional(2-D) Array or Multi-Dimentional array
Advantages of array:
- Array represent multiple data elements of the same type using a single name.
- In arrays, the elements can be accessed randomly by using the index number.
- Array consist of contiguous memory locations therefore there is no chance of extra memory being allocated in case of arrays
- 2D Array is used to represent matrices.
- Using arrays, we can implement other data structure like stack, queues, linked list, trees, graphs etc.
Disadvantages of Array:
- Using arrays, we can implement other data structure like stack, queues, linked list, trees, graphs etc.
- Allocating more memory than the requirement leads to wastage of memory and less allocation of memory leads problem.
- Insertion and deletion quit difficult in an arrays.
- The array is homogeneous(means only one type of value can be store in the array.
Applications:
- A basic application of arrays can be storing data in tabular format.
- 2D arrays known as matrix,are used in image processing.
- Arrays can be used for CPU scheduling.
- Arrays are used to implement mathematical vectors, matrices and rectangular table.
- Arrays are used to implement data structures like stack, queue, linked list, trees, graphs etc.
Sample Programs
1. Initialization of 1-D array at compile time
// Print the elements stored in the array
#include<stdio.h>
#include<conio.h>
void main()
{
int a[5]={1,2,3,4,5};
clrscr();
// printing elements of an array
for(int i = 0; i < 5; i++)
{
printf("%d\n", a[i]);
}
getch();
}
output:
1
2
3
4
5
2. Initialization of 1-D array at run time
// Print the elements stored in the array
#include<stdio.h>
#include<conio.h>
void main()
{
int a[5];
clrscr();
printf("Enter 5 elements in the array/n");
scanf("&d", &a[i]);
// taking input and storing it in an array
for( i = 0; i < 5; i++) {
scanf("%d", &a[i]);
}
printf("Displaying array elements/n");
// printing elements of an array
for(int i = 0; i < 5; i++)
{
printf("%d\n", a[i]);
}
getch();
}
Output:
Enter 5 elements in the array
10
20
30
40
50
Displaying array elements
10
20
30
40
50
3.Sum of array 1-D elements
//Print sum of array elements
#include<stdio.h>
int main()
{
int array[5];
int sum, i;
sum = 0;
printf("Enter values in 1-D array/n")
for(i = 0; i < 6; i++);
{
scanf("%d",array[i]);
}
for(i = 0; i < 6; i++)
{
sum = sum + array[i];
}
printf("Sum of array is %d", sum);
return 0;
}
Output:
Enter values in 1-D array
1
2
3
4
5
Sum of array is 15
4. Initialization of 2-D array at compile time
//program for compile time array initialization
#include<stdio.h>
void main()
{
int a[2][2]={{1,2},{3,4}};
int i,j;
printf(“Array elements are\n”);
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
{
printf(“%d\n”,a[i][j]);
}
}
return 0;
}
Output:
Array elements are
1 2
3 4
5. Initialization of 2-D array at run time
// Print the elements stored in the array
#include<stdio.h>
void main()
{
int a[2][2];
int i,j;
printf(“Enter the array elements \n”);
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
{
scanf(“%d”,&a[i][j]);
}
}
printf(“Array elements are \n”);
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
{
printf(“%d\n”,a[i][j]);
}
}
return 0;
}
Output:
Enter the array elements
5
6
7
8
Array elements are
5 6
7 8
Examples For Practice
- Implement C program to find smallest element in a 1-D array
- Implement C program to find the average of N elements of 1-D array. (Read N from user).
- Implement C program to find the sum of all elements in a 2-D array.
- Implement C program to display even and odd numbers from given 2-D array