Explain the insertion sort by using C language.

Sorting is the process of arranging the elements either in ascending (or) descending order.

Types of sorting

C language provides five sorting techniques, which are as follows −

• Bubble sort (or) Exchange Sort
• Selection sort
• Insertion sort(or) Linear sort
• Quick sort (or) Partition exchange sort
• Merge Sort (or) External sort

Insertion Sort

The logic used to sort the elements by using the insertion sort technique is as follows −

for(i = 1; i <= n - 1; i++){
   for(j = i; j > 0 && a[j - 1] > a[j]; j--){
      t = a[j];
      a[j] = a[j - 1];
      a[j - 1] = t;
   }
}

Explanation

Let us consider some elements which are in unsorted order −

Example

Following is the C program to sort the elements by using the insertion sort technique −

#include<stdio.h>
int main() {
   int a[50], i,j,n,t;
   printf("enter the No: of elements in the list:\n");
   scanf("%d", &n);
   printf("enter the elements:\n");
   for(i=0; i<n; i++){
      scanf ("%d", &a[i]);
   }
   for(i = 1; i <= n - 1; i++){
      for(j=i; j > 0 && a[j - 1] > a[j]; j--){
         t = a[j];
         a[j] = a[j - 1];
         a[j - 1] = t;
      }
   }
   printf ("after insertion sorting the elements are:\n");
   for (i=0; i<n; i++)
   printf("%d\t", a[i]);
   return 0;
}

Output

When the above program is executed, it produces the following output −

Enter the No: of elements in the list:
10
Enter the elements:
34
125
2
6
78
49
1
3
89
23
After insertion sorting the elements are:
1 2 3 6 23 34 49 78 89 125