Remove Duplicate Characters from a String

Code

#include <stdio.h>
#include <stdint.h>

void remove_duplicates(char *str) {
    int l=0;
    int length=0;
    while(str[length]!='\0')
    {
        length++;
    }
    while(str[l]!='\0')
    {
        if(l==0)
        {
            l++;
        }
        for(int i=0;i<l;i++)
        {
            if(str[l]==str[i])
            {
                for(int j=l;j<length;j++)
                {
                    str[j]=str[j+1];
                }
                l--;
            }
        }
        l++;
    }
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    remove_duplicates(str);
    printf("%s", str);
    return 0;
}

Solving Approach