Arrange the alphabets in a string in descending order ID:2

A string (with only alphabets) S is passed as input. The program should print the alphabets in the string in descending order. Assume all alphabets will be in lower case.

Boundary Conditions:
The length of string S is between 2 and 100.

Example input and output:

If the input is "cake", the output should be "keca"
If the input is "innovation", the output should be "vtonia" (n or o or i should not be repeated)

#include <stdio.h>

int main()

{

char s[100];

scanf("%[^\n]s",s);

int num[26]={0};

for(int i=0;i<strlen(s);i++)

{

    num[s[i]-97]=1;

}

for(int i=25;i>=0;i--)

{

    if(num[i]==1)

    {

       printf("%c",(char)(i+97));

    }

}

}