Remove Duplicate Characters from a String

Code

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

void remove_duplicates(char *str) {
	//Your logic here
    int alphabet[75] = {0};
    char* c = str;
    while(*c!='\0'){
        if(*c == ' ')
            c++;
        if(alphabet[*c -'0'] == 0){
            alphabet[*c -'0'] = 1;
            c++;

        }else{
            char *c2 = c;
            while(*c2 != '\0'){
                if(*c2 == ' ')
                    c2++;
                 *c2 = *(c2 + 1);
                 c2++;
            }
        }

    }
}

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