Count the number of duplicate elements in an array-C

[sharbu]

Accept an Array of size N and print the total number of duplicate elements (The elements which occur two or more times).
Input Format: The first line contains N. The second line contains the N positive integer values, each separated by a space.
Output Format: The first line contains the count of duplicate elements.

The program I wrote works for only two same elements and fails to read more than 2 duplicates.

#include<stdio.h>
#include <stdlib.h>

int main()
{
    int arr[1000],i,j,n,count=0;
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        scanf("%d",&arr[i]);

    }
    
    for(i=0;i<n;i++)
    {
        for(j=i+1;j<n;j++)
        {
          
            
                if(arr[i]==arr[j])
                {
                    count=count+1;
                    break;
                }
            
        }
    }
    printf("%d",count);

}

Input: n=8
1 2 3 1 2 1 5 6

Here the program returns 3 instead of 2 because of 3 duplicates(1 1 1).
Suggest some ideas to avoid this...

[elohssa]

#include <unordered_map>

auto countDuplicutes(int arr[1000])
{
std::unordered_map<int, int> retv;
for(int i = 0; i < 1000; ++i)
++retv[iarr[i]];


return retv;
}

countDuplicutes returns key/value map where key = number and value = number of times number appears in array

[sharbu]

Figured it out :)

#include<stdio.h>
#include <stdlib.h>
 
int main()
{
 int arr[1000],temp,i,j,n,count=0;
 scanf("%d",&n);
 for(i=0;i<n;i++)
  {
  scanf("%d",&arr[i]);
 
  }
 
 for(i=0;i<n;++i)
{
  for(j=i+1;j<n;++j)
 {
  if(arr[i]>arr[j])
  {
   temp=arr[i];
   arr[i]=arr[j];
   arr[j]=temp;
  }
 }
}
 
for(i=0;i<n;i++)
 {
  for(j=i+1;j<n;j++)
   {
   if(arr[i]==arr[j])
   continue;
   else if(i!=j-1)
   count++;
   i=j;
   }
  }
 printf("%d",count);
 return 0;
 
}