Rewrite string characters alphabetically

Logic. Every character of the string is compared with the characters after it (a simple exchange sort). Whenever a later character has a smaller ASCII value, the two are swapped. After the loops the characters are in ascending order. For mixed upper and lower case letters, convert the string to one case first (tolower), because capital letters have smaller ASCII codes than small letters.

#include <stdio.h>
#include <string.h>

int main(void)
{
    char s[100], t;
    printf("Enter a string: ");
    scanf("%99s", s);
    int n = strlen(s);

    for (int i = 0; i < n - 1; i++)
        for (int j = i + 1; j < n; j++)
            if (s[i] > s[j]) {             /* swap to keep smaller first */
                t = s[i];
                s[i] = s[j];
                s[j] = t;
            }
    printf("Characters in alphabetical order: %s\n", s);
    return 0;
}

Sample run

Input: computer

Enter a string: Characters in alphabetical order: cemoprtu