In this post, we will learn how to find the unique elements in an array, such that the repetitive elements in the array will be displayed only once.

Let's write a C program to find unique elements in an array.

C Program to Find Unique Elements in an Array

Let's create a file named uniqueelements.c and add the following source code to it.

#include<stdio.h> 
#define max 100

int ifexists(int z[], int u, int v)
{
	int i;
	for (i=0; i<u;i++)
		if (z[i]==v) return (1);
	return (0);
}


void main()
{
	int p[max], q[max];
	int m;
	int i,k;
	k=0;
	printf("Enter length of the array:"); 
	scanf("%d",&m); 
	printf("Enter %d elements of th array\n",m); 
	for(i=0;i<m;i++ )
		scanf("%d",&p[i]); 
	q[0]=p[0];
	k=1;
	for (i=1;i<m;i++)
	{
		if(!ifexists(q,k,p[i]))
		{
			q[k]=p[i];
			k++;
		}
	}
	printf("\nThe unique elements in the array are:\n"); 

	for(i = 0;i<k;i++)
		printf("%d\n",q[i]); 
}

To compile and run the above C program, you can use C Programs Compiler Online tool.

Output:

Enter the length of the array:5
Enter 5 elements in the array
1
2
3
2
1

The unique elements in the array are:
1
2
3