edit7.c

里面有很多的例子

createtree(struct btree **tree){
	char ch;
	printf("\n input the date:");
	ch=getch(); printf("%c",ch);
	if(ch==' ')(*tree)=NULL;
	else {
		(*tree)=(struct btree *)malloc(sizeof(struct btree ));
		if((*tree)==NULL){
			printf("malloc failed, press any key to back");
			getch();
		}
		else {
			(*tree)->data=ch;
			createtree(&(*tree)->left);
			createtree(&(*tree)->right);
		}
	}

}