C Program To Remove Duplicate Elements in an Array

In this tutorial, we are going to see how to write a C program to remove duplicate elements in an array. For example, if an array contains the following elements: 1, 1, 2, 2, 3, 4; So ‘1’ and ‘2’ occur twice. After deleting the duplicated element, we get the following array: 1, 2, 3, 4.
 

C Program To Remove Duplicate Elements in an Array

#include <stdio.h>
 
int main() {
   int nbr, i, j, k;
   int arr[30];
 
   printf("Enter the number of elements in the array: ");
   scanf("%d", &nbr);
 
   printf("Enter the array elements: ");
   for (i = 0; i < nbr; i++)
      scanf("%d", &arr[i]);
 
   // Remove duplicates
   for (i = 0; i < nbr; i++) {
      for (j = i + 1; j < nbr;) {
         if (arr[j] == arr[i]) {
            for (k = j; k < nbr; k++) {
               arr[k] = arr[k + 1];
            }
            nbr--;
         } else
            j++;
      }
   }
 
   printf("Array without duplicates: ");
   for (i = 0; i < nbr; i++) {
      printf("%d ", arr[i]);
   }
 
   return 0;
}

Output:

Enter the number of elements in the array: 6
Enter the array elements: 1 1 2 2 3 4
Array without duplicates: 1 2 3 4

 
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