7、編寫一個程序，能打開、讀入一個文本文件并統計文件中每個單詞出現的次數。用改進的二叉搜索樹存儲單詞及其出現的次數。程序讀入文件后，會提供一個有三個選項的菜單。第一個選項為列出所有單詞連同其出現的次數。第二個選項為讓您輸入一個單詞，程序報告該單詞在文件中出現的次數。第三個選項為退出。

斷斷續續編寫代碼、測試，花了差不多兩天時間，總算告成。

*建立該問題的二叉樹節點模型

//BST Model--START------------------ typedef struct node {char word[15];int times; //出現的次數struct node *left;struct node *right; }Node;typedef struct tree {Node *root;int num; //樹中單詞數 }Tree; //BST Model--FINISH--------------------

*研究本題需求，實現接口代碼

//BST function START----------------------------- //初始化樹 void IniTree(Tree *ptree) {ptree->root=NULL;ptree->num=0; }//查找樹中有無指定單詞 //若未找到，返回NULL；若找到返回指定項目所在節點地址 Node *FindWord(char word[15],const Node *root) {Node *pnode;pnode=root;if(root==NULL){return NULL;}while(strcmp(word,pnode->word)!=0 && (pnode!=NULL)){ if(strcmp(word,pnode->word)<0)pnode=pnode->left;elsepnode=pnode->right;}return pnode; }//添加單詞節點 //通過FindWord做支撐，若存在，則相應節點次數+1 //若不存在，則找到合適的空位，同時定位該空位的父節點 //創建該單詞的節點，并判斷在空位父節點的左還是右，然后添加 void AddWord(char word[15],Tree *ptree) {Node *pnode,*newnode,*fathernode;pnode=FindWord(word,ptree->root);if(pnode!=NULL){ pnode->times++;}else{newnode=ptree->root;while(newnode!=NULL) //找空位，并且定位空位的父節點 {if(strcmp(word,newnode->word)<0){fathernode=newnode; newnode=newnode->left;}else{fathernode=newnode; newnode=newnode->right;}} newnode=(Node*)malloc(sizeof(Node));newnode->left=NULL;newnode->right=NULL;newnode->times=1;strcpy(newnode->word,word); //設置節點信息if(ptree->root==NULL) //如果樹為空 {ptree->root=newnode;ptree->num++; }else{if(strcmp(word,fathernode->word)<0) //說明父節點左子節點為空 { fathernode->left=newnode;ptree->num++;}else{ fathernode->right=newnode;ptree->num++;}}} }//打印樹中單詞信息 void PrintTree(const Node *root) {if(root!=NULL){ PrintTree(root->left);printf("the word is %s,its times is %d.\n",root->word,root->times);PrintTree(root->right);} }//輸入單詞，顯示次數 void showtimes(const Tree *ptree) {Node *pnode;char word[15];printf("input the word.\n");gets(word);pnode=FindWord(word,ptree->root);if(pnode==NULL)printf("the word:%s is not in the tree.\n",word);elseprintf("the word:%s times in tree is:%d.\n",word,pnode->times);} //BST function FINISH---------------

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*完整代碼：

#include<stdio.h> #include<string.h> #include<stdlib.h>//BST Model--START------------------ typedef struct node {char word[15];int times;
struct node *left;struct node *right; }Node;typedef struct tree {Node *root;int num;
}Tree; //BST Model--FINISH--------------------//BST function START----------------------------- //初始化樹 void IniTree(Tree *ptree) {ptree->root=NULL;ptree->num=0; }//查找樹中有無指定單詞 Node *FindWord(char word[15],const Node *root) {Node *pnode;pnode=root;if(root==NULL){return NULL;}while(strcmp(word,pnode->word)!=0 && (pnode!=NULL)){ if(strcmp(word,pnode->word)<0)pnode=pnode->left;elsepnode=pnode->right;}return pnode; }//添加單詞節點 void AddWord(char word[15],Tree *ptree) {Node *pnode,*newnode,*fathernode;pnode=FindWord(word,ptree->root);if(pnode!=NULL){ pnode->times++;}else{newnode=ptree->root;while(newnode!=NULL)
{if(strcmp(word,newnode->word)<0){fathernode=newnode; newnode=newnode->left;}else{fathernode=newnode; newnode=newnode->right;}} newnode=(Node*)malloc(sizeof(Node));newnode->left=NULL;newnode->right=NULL;newnode->times=1;strcpy(newnode->word,word);
if(ptree->root==NULL)
{ptree->root=newnode;ptree->num++; }else{if(strcmp(word,fathernode->word)<0)
{ fathernode->left=newnode;ptree->num++;}else{ fathernode->right=newnode;ptree->num++;}}} }//打印樹中單詞信息 void PrintTree(const Node *root) {if(root!=NULL){ PrintTree(root->left);printf("the word is %s,its times is %d.\n",root->word,root->times);PrintTree(root->right);} }//輸入單詞，顯示次數 void showtimes(const Tree *ptree) {Node *pnode;char word[15];printf("input the word.\n");gets(word);pnode=FindWord(word,ptree->root);if(pnode==NULL)printf("the word:%s is not in the tree.\n",word);elseprintf("the word:%s times in tree is:%d.\n",word,pnode->times);} //BST function FINISH---------------int main() {FILE *fp;Tree *wordtree;Node *new_node;char newword[15];char ch,cc;int i=0; //讀入文件，創建單詞的二叉搜索樹-----------------------fp=fopen("ab.txt","r");if(fp==NULL){fprintf(stdout,"can't open the file.\n");getch();exit(1);} //初始化樹 IniTree(wordtree);//讀入文件字符while((ch=getc(fp))!=EOF){if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z')){newword[i]=ch;i++;}else{if(i==0)
continue;else
{newword[i]='\0';AddWord(newword,wordtree); //加入單詞樹i=0;}}} //針對文本最后字符為字母，則還未設置字符串結束符就跳出while循環了 //增加本段代碼處理if(i!=0){newword[i]='\0';AddWord(newword,wordtree); //加入單詞樹 } //單詞二叉搜索樹創建完成--------------------------------------------------------- printf("-----Please choose--------\n");printf("a:---show all words-------\n");printf("b:---some word------------\n");printf("c:---Quit-----------------\n");while((cc=getch())!='c'){switch(cc){case 'a':PrintTree(wordtree->root);break;case 'b':showtimes(wordtree);break;}printf("-----Please choose--------\n");printf("a:---show all words-------\n");printf("b:---some word------------\n");printf("c:---Quit-----------------\n");}fclose(fp);return 0; }

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轉載于:https://www.cnblogs.com/tsembrace/p/3194344.html

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