void print_by_name () {
    int i,j,k;
    struct phonebook *temp,**entry2;
    entry2=(struct phonebook **)malloc(phone_size*sizeof(struct phonebook*));
    if (entry2==NULL) {
        printf("MEMORY ERROR!\n");
        return;
    }    
    for (i=0; i<phone_size; i++) {
	    entry2[i]=entry[i];
    }      
    for (i=0; i<phone_size; i++) {
        for (j=i+1; j<phone_size; j++) {
            //for (k=0; k<64; k++) {
                if (strcmp(entry2[i]->username,entry2[j]->username)>0) {
                    temp=entry2[i];
                    entry2[i]=entry2[j];
                    entry2[j]=temp;
                    break;
                }
            //}
        }
    }                    
    printf("code username region time\n");
    for (i=0; i<phone_size; i++) {
        printf("%d %s %s %d\n",entry2[i]->code,entry2[i]->username,entry2[i]->region,entry2[i]->time);
    }
    printf("\n");
    free(entry2);
}