树转存广义表
save.c

#include<stdio.h>
#include<stdlib.h>#define FNAME "/tmp/out"struct node_st
{char data;struct node_st *l,*r;
};static struct node_st *tree = NULL;//把tree提升到全局变量,当前文件int insert(struct node_st **root,int data)
{struct node_st *node;if(*root == NULL){node = malloc(sizeof(*node));if(node == NULL)return -1;node->data = data;node->l = NULL;node->r = NULL;*root = node;return 0;}if(data <= (*root)->data)return insert(&(*root)->l,data);elsereturn insert(&(*root)->r,data);
}void draw_(struct node_st *root,int level)
{int i;if(root == NULL)return ;draw_(root->r,level+1);for(i = 0;i<level;i++)printf("    ");printf("%c\n",root->data);draw_(root->l,level+1);
}
void draw(struct node_st *root)
{draw_(root,0);printf("\n\n");//getchar();//相当于暂停
}int save_(struct node_st *root,FILE *fp)
{fputc('(',fp);/*if error*/if(root == NULL){fputc(')',fp);return 0;}fputc(root->data,fp);/*if error*/save_(root->l,fp);save_(root->r,fp);fputc(')',fp);/*if error*/return 0;
}int save(struct node_st *root,const char *path)
{FILE *fp;fp = fopen(path,"w");if(fp == NULL)return -1;save_(tree,fp);fclose(fp); // 别忘了关闭文件return 0;
}int main()
{char arr[] = "cefadjbh";int i;for(i = 0;i<sizeof(arr)/sizeof(*arr) - 1;i++){insert(&tree,arr[i]);}draw(tree);save(tree,FNAME);exit(0);
}

广义表转成树
load.c

#include<stdio.h>
#include<stdlib.h>#define FNAME "/tmp/out"struct node_st
{char data;struct node_st *l,*r;
};void draw_(struct node_st *root,int level)
{int i;if(root == NULL)return ;draw_(root->r,level+1);for(i = 0;i<level;i++)printf("    ");printf("%c\n",root->data);draw_(root->l,level+1);
}
void draw(struct node_st *root)
{draw_(root,0);printf("\n\n");//getchar();//相当于暂停
}struct node_st *load_(FILE *fp)
{int c;struct node_st *root;c = fgetc(fp);if(c != '('){fprintf(stderr,"fgetc():error.\n");exit(1);}c = fgetc(fp);if(c == ')')return NULL;root = malloc(sizeof(*root));if(root == NULL)exit(1);root->data = c;root->l = load_(fp);root->r = load_(fp);fgetc(fp);/*if error */return root;
}load(const char *path)
{FILE *fp;struct node_st *root;fp = fopen(path,"r");if(fp == NULL)return NULL;root = load_(fp);fclose(fp);return root;}int main()
{struct node_st *root;root = load(FNAME);draw(root);exit(0);
}