Remove Duplicate Characters from a String

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

char* deleteCharC(char* s, char ch, int len) {
    int i, j;
    for (i = j = 0; i < len; i++) {
        if (s[i] != ch) {
            s[j++] = s[i];
        }
    }
    s[j] = '\0';
    return s;
}

void remove_duplicates(char *str) {
	//Your logic here
    int len = 0;
    while(*str){
        len++;
        str++;
    }
    str = str-len;
    for(int i=0 ; i<len ; i++){
        for(int j=i+1 ; j<len; j++){
            if(str[i]==str[j]){
                str[j] = '=';
            }
        }
    }
    deleteCharC(str,'=',len);
    }

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;
}