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我試圖插入到我的BST,但我努力創建一個循環。 當我逐一插入代碼時,該代碼有效,但當我嘗試將其放入循環中時,它無法正確插入。在CST的循環中插入節點B
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h> // for strcmp()
#include <ctype.h> // for toupper()
typedef struct BstNode{
//char name[20];
// int data;
struct BstNode* left;
struct BstNode* right;
char* name;
}BstNode;
typedef int (*Compare)(const char*, const char*); // makes comparisons easier
/* Returns pointer address to newly created node */
BstNode* createNode(char* name){
BstNode* newNode = (BstNode*)malloc(sizeof(BstNode)); // Allocates memory for the newNode
newNode->name = name; // newNode->data is like newNode.data
newNode->left= NULL;
newNode->right = NULL;
return newNode;
}
//insert node into Tree recursively
BstNode* insertNode(BstNode* node, char* name, Compare cmp){
int i;
/* char *s1 = node->name;
char *s2 = name;
printf("s1: %s, s2: %s\n", s1,s2);
i = strcmp(s1, s2); // if =1, s1 is greater
printf("i: %d\n", i); */
if(node == NULL){// if tree is empty
// printf("inside NULL\n");
node = createNode(name);
//return node;
}
else{
i = cmp (name, node->name); // sweet
if(i == -1){
// printf("inside left\n");
node->left = insertNode(node->left, name, cmp);
//return node;
}
else if(i == 1){
// printf("inside right\n");
node->right = insertNode(node->right, name, cmp);
//return node;
}
else if(i == 0){ //avoid duplicates for now
// printf("inside 0\n");
printf("Name is in BST\n");
return NULL;
}
}
return node;
}
BstNode* printTree(BstNode* node){
if(node == NULL){
return NULL;
}
printTree(node->left);
printf("%s\n",node->name);
printTree(node->right);
}
int CmpStr(const char* a, const char* b){
return (strcmp (a, b)); // string comparison instead of pointer comparison
}
//void Insert(Person *root, char name[20]);
int main(){
BstNode* root = NULL; // pointer to the root of the tree
char buf[100];
char option = 'a';
while(1) {
printf("Enter employee name");
scanf("%s",buf);
printf ("Inserting %s\n", buf);
root = insertNode(root, buf, (Compare)CmpStr);
printTree(root);
}
}
我能做的根= insertNode(根,名稱,(比較)CmpStr) 代碼幾次,但如果我嘗試與用戶輸入迴路它不會正確插入。我不確定它是否與我正在使用scanf()或root沒有正確設置的事實有關。我也嘗試過使用fgets(),但我不太清楚如何使用它並不斷弄亂它。 任何幫助表示讚賞。
'root = insertNode(root,buf,(Compare)CmpStr);'你所有的節點指向同一個緩衝區。 ('newNode-> name = name;'在createnode()中)buf在main中。您應該在newnode() – wildplasser
中執行strdup或simalar我不知道這是否是您的問題,但是'strcmp'不會返回1或0或-1。它返回「小於零」,0或「大於零」。 (大多數實現依賴於減去相應的字符值,所以想想''f' - 'a''和'a' - 'a'和'a' - 'f'...) –
@wildplasser好的!這可能是。 –