（含字元選擇排序，字串去重介面）實驗7-3-10 刪除重複字元 (20分)

#include<stdio.h>
#include<ctype.h>
#include<string.h>
#include<math.h>
#include<stdlib.h>
void sort( char arr[], int n ){
    char temp;
    int i, j;
    for ( i = 0; i < n - 1; i++)
        for ( j = i + 1; j < n; j++)
            if (arr[i] >= arr[j]){
                temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        
}
void RemoveDuplicate(char *s)
{
	char check[256] = { 0 };
	int i, j, len;
	len = strlen(s);
	for(i = j = 0; i < len; i++)
	{
		if(check[s[i]] == 0)
		{
			s[j++] = s[i];
			check[s[i]] = 1;
		}
	}
	s[j] = '\0';
}
int main()
{	
	int arr[81];
	gets(arr);
    int len = strlen(arr), i, j;
    sort(arr, len);
    RemoveDuplicate(arr);
    puts(arr);
	return 0;
}