Arrays in C | Array Programs in C
Hello friends,Today we will discuss about Arrays in C language.
Arrays is a very popular and useful data structure used to store data elements in a contiguous memory location.It stores similar types of elements or values under one variable.Suppose if you declare integer type variable it stores only integer types of values.
syntax:
datatype variable-name [size of elements];
for example:
int num[5];
or
int num[5]={1,2,4,5,3};
Here,Five elements are stored in array 'num'.Array elements are stored sequentially in separate locations.Arrays element has its own index number which is started by 0.It means we can access or initialize individual elements by its index number.Index number is also called as subscript number.
for example:
int num[5]={1,4,3,5,7};
num[0]=1;
num[1]=4;
num[2]=3;
num[3]=5;
num[4]=7;
Points to Remember
- All the elements of an array share the same name.
- They are distinguished from one another with the help of the element number or index number.
- The index number is used to access the value of individual element.
- We can modify the value of any element by its index number without hurting another element.
- If you want to delete,modify,replace any value ,you need not require changing all other elements.
- Any element of an array can be assigned to another ordinary variable or any array variable.
num2[5]={1,2,4,7,8};
num1=num[3];
num[3]=num[5];
- When an array declared and not initialized,it contains garbage values.
- The amount of memory required for an array depends upon the data type and the number of elements.
Array Programs in C
One-Dimensional Array and Operations
Array elements are stored contiguously in sequence one after the other. The elements of an array are just arranged in one – dimensional array to represent its elements.
We learned how to declare, initialise and access the array elements.
We will learn how to traverse, insert, delete and display elements in the array during program execution.
Traversing: The operation of displaying or listing all elements of an array is called traversing. The following program explains traversing with one-dimensional array.
Write a program to read and display the elements of an array.
Void main ()
{
clrscr ();
int num [5], j;
printf (“\n Enter five elements:”);
for (j=0; j<=5; j++)
scanf (“%d”, &num[j]);
printf (“\n Element Address”);
for (j=0; j<5; j++)
printf (“\n%d %u”, num[j], &num[j]);
getch ();
}
ScreenShot :
Here, In the above program, an array num [] is declared. The first for loop with the help of scanf () statement reads the elements and places in the array. The element position is indicated by the loop variable j. Same procedure is applied for displaying elements. The printf () statement displays the elements and addresses on the screen.
In an array we can insert, delete or add any element but we cannot insert or delete the memory location. We can change only values.
Deletion: This operation involves deleting specified elements from an array and rearrange the elements.
Write a program to delete specified element from an array and rearrange the elements.
Void main ()
{
int num [20]={0};
int j,k,n,p,t;
printf(“\n Enter number of elements : ”);
scanf (“%d”,&n );
printf(“/n Enter elements : ”);
for(j=0;j<n;j++)
scanf(“%d”,&num[j]);
printf(“\n Elements are : ”);
for(j=0;j<n;j++)
printf (“\n %d %u”, num[j],&num[j]);
printf (“\n Enter element number to delete:”);
scanf (“%d”, &p);
--p;
for (j=0; j<n; j++)
{
If(j>=p)
num[j]=num[j+1];
}
for (j=0; j<n; j++)
{
If(num[j]! =0)
printf (“\n %d %u”, num[j], &num[j]);
}
getch ();
}
Screenshot:
Here, an array num [20] is declared. The program asks for the number of elements to be entered. User has to enter the following input.
Number of elements to be entered and integers.
Element number to be erased from an array.
The first loop and scanf () statement reads numbers from keyboard and places in the array. In the second for loop onward the position of an element number is to be erased, the next array element is replaced with the previous one. Thus, the specified element is removed from an array. The third for loop and printf () statement display the elements of an array. You can see in the output that the third memory location is the same only if its contents are changed.
Insertion : This operation is used to insert an element at a specified position in an array .
Write a program to insert an element at a specified position in an array.
Void main ()
{
int num [20]={0};
int j,k,n,p,t,s;
printf(“\n Enter number of elements : ”);
scanf (“%d”,&n );
printf(“/n Enter elements : ”);
for(j=0;j<n;j++)
scanf(“%d”,&num[j]);
printf(“\n Elements are : ”);
for(j=0;j<n;j++)
printf (“\n %d %u”, num[j],&num[j]);
printf (“\n Enter element number to delete:”);
scanf (“%d %d”,&s, &p);
p--;
for (j=n; j>=p; j++)
{
num[j+1]=num[j];
Num[j]=s;
}
for (j=0; j<=n; j++)
{
printf (“\n %d %u”, num[j], &num[j]);
}
getch ();
}
Screenshot:
Here, an element is inserted. The array elements are shifted to the next location and at a specified position and a space is created and inserted new element. Here , you can also see that though we inserted a new element, the memory location of the second element is the same.Once again it is proved that in array operation only contents of memory can change but the actual addresses remain as it is.The address of the first element is called the base address.This address can be stored in another pointer and array element can be accessed.
Array Search Element
Searching: An array element can be searched. This process of seeking specific elements in an array is called searching.
Write a program to search a specified element in an array
Void main ()
{
clrscr();
int n,i;
int x[10]={2,2,3,4,2,4,4,,6,8,7};
printf(“\n Array elements are : ”);
for(i=0;i<=9;i++)
{
printf(“%d”,x[i]);
}
printf(“\n Enter the element to search in an array : ”);
scanf(“%d”,&n);
for(i=0;i<10;i++)
{
if(x[i]==n)
flag=0;
break;
else
flag=1
}
if(flag==0)
printf(“Element found”);
else
printf(“Element not found”);
getch ();
}
Screenshot :
Here, an integer array is initialised with elements.The element which is to be searched is entered through the user.using a for loop all the elements are read.The if statement checks every element with the array elements.When the if condition satisfies the message ‘element found’ message is displayed.Thus,the specified element can be searched . Message ‘element not found’ is displayed when an element is not searched.
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