Remove Duplicate Characters from a String

Code

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

int temp[300]; 

void reset_temp(int *temp){
    for(int i = 0; i<300; i++){
        temp[i] = 0;
    }
}

int delete_duplicate_string(char *str, char *out, int* temp){
    int count = 0;
    for(int i = 0; i<strlen(str); i++){
        if(temp[str[i]] == 0){
            out[count] = str[i];
            temp[str[i]]++; 
            count++; 
        }
    }
    out[count] = '\0';
    return count;
}

int main(){
    char str[101]; 
    char out[101];
    fgets(str, sizeof(str), stdin);
    str[strcspn(str,"\n")] = '\0';
    reset_temp(temp);
    int count = delete_duplicate_string(str, out, temp);
    if(count != 0){
        printf("%s",out);
    }
    else{
        printf("deo co cai l gi");
    }

    return 0;
}  

Solving Approach