Array Exercises
Write a C program to delete duplicate elements from array. How to remove duplicate elements from array in C programming. After performing delete operation the array should only contain unique integer value. Logic to delete duplicate elements from array.
Required knowledge
Basic C programming, If else, c-Arrays, C Loops
Logic to delete duplicate elements from array
Step by step descriptive logic to delete duplicate elements from array.
- Input size and elements in array from user. Store it in some variable say size and arr.
- To find duplicate elements in given array we need two loops. Run an outer loop from 0 to size. Loop structure must look like for(i=0; i<size; i++). This loop is used to select each element of array and check next subsequent elements for duplicates using another nested loop.
- Run another inner loop to find first duplicate of current element. Run an inner loop from i + 1 to size. The loop structure should look like for(j=i+1; j<size; j++).
- Inside the inner loop check for duplicate element. If a duplicate element is found then delete that array element. Also if a duplicate element is found then decrement size of array i.e. size = size - 1.
Program to delete duplicate elements from array
/**
* C program to delete all duplicate elements from array
*/
#include <stdio.h>
#define MAX_SIZE 100 // Maximum size of the array
int main()
{
int arr[MAX_SIZE]; // Declares an array of size 100
int size; // Total number of elements in array
int i, j, k; // Loop control variables
/* Input size of the array */
printf("Enter size of the array : ");
scanf("%d", &size);
/* Input elements in the array */
printf("Enter elements in array : ");
for(i=0; i<size; i++)
{
scanf("%d", &arr[i]);
}
/*
* Find duplicate elements in array
*/
for(i=0; i<size; i++)
{
for(j=i+1; j<size; j++)
{
/* If any duplicate found */
if(arr[i] == arr[j])
{
/* Delete the current duplicate element */
for(k=j; k<size; k++)
{
arr[k] = arr[k + 1];
}
/* Decrement size after removing duplicate element */
size--;
/* If shifting of elements occur then don't increment j */
j--;
}
}
}
/*
* Print array after deleting duplicate elements
*/
printf("\nArray elements after deleting duplicates : ");
for(i=0; i<size; i++)
{
printf("%d\t", arr[i]);
}
return 0;
}
