frPtr=*lPtr;
        //istogramma
    int o=0;
    while(frPtr!=NULL){
    o=0;
    while((frPtr->prossimoPtr != NULL) &&(strcmp(frPtr->dato, frPtr->prossimoPtr)==0)){
        o++;
        frPtr=frPtr->prossimoPtr;
    }
    fprintf(fptr, "%15s", frPtr->dato);
    for(int i=0;i<=o;i++){
        fprintf(fptr, "*");
    }
    fprintf(fptr, "\n");
    frPtr=frPtr->prossimoPtr;
    }

    fclose(fptr);
    }