[英]Circular Doubly Linked List- Delete node
我正在构建循环双向链表代码。
在我的代码中,有四个函数——添加节点、删除节点、顺时针打印、逆时针打印。 除了删除 function 之外,我所有的代码都可以正常工作。 if(recycle->name == x)
行似乎无法正常工作,并且free(recycle)
也没有成功释放回收节点。
我的原始代码是。 如下
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define nameLen 20
struct Node
{
char name[nameLen];
struct Node *left; //next
struct Node *right; //previous
};
struct Node* current;
struct Node* head;
int count = 0;
struct Node* GetNewNode(char *x)
{
struct Node* newNode;
newNode = (struct Node*)malloc(sizeof(struct Node));
strncpy(newNode->name, x, nameLen);
newNode->left = NULL;
newNode->right = NULL;
return newNode;
}
void add_name(char *x)
{
struct Node* temp = current;
struct Node* newNode = GetNewNode(x);
count++;
if(current == NULL)
{
current = newNode;
head = current;
}
else
{
current->left = newNode;
newNode->right = temp;
current = newNode;
current->left = head;
head->right = current;
}
printf("Add %s into database.\n\n", current->name);
}
void delete_name(char *x)
{
int i, j;
struct Node* recycle = current;
if(current == NULL)
{
printf("No data input.");
}
else
{
for (i = 0; i < count; i++)
{
if(recycle->name == x)
{
free(recycle);
j++;
printf("Delete %s from database.\n", x);
}
recycle = recycle->left;
}
if(j == 0)
{
printf("There is no %s in data", x);
}
current = recycle;
}
}
void print_clock(int number)
{
int i;
struct Node* temp = current;
if(temp == NULL)
{
printf("No data input.");
}
else
{
printf("Clockwise: \n");
for(i = 0; i < number; i++)
{
printf("%s ",temp->name);
temp = temp->left;
}
}
printf("\n\n");
}
void print_counter(int number)
{
int i;
struct Node* temp = current;
if(temp == NULL)
{
printf("No data input.");
}
else
{
printf("Counterclockwise: \n");
for(i = 0; i < number; i++)
{
printf("%s ",temp->name);
temp = temp->right;
}
}
printf("\n\n");
}
int main()
{
char s1;
char s2[nameLen];
char name[nameLen];
int number;
while(1)
{
printf("Enter the instruction: ");
scanf("%s %s", &s1, s2);
if (s1 == '+' && sscanf(s2, "%d", &number) == 1)
{
printf("Print out %d name(s) clockwise.\n", number);
print_clock(number);
}
else if (s1 == '-' && sscanf(s2, "%d", &number) == 1)
{
printf("Print out %d name(s) counterclockwise.\n", number);
print_counter(number);
}
else if (s1 == '+' && sscanf(s2, "%s", name) == 1)
{
add_name(s2);
}
else if (s1 == '-' && sscanf(s2, "%s", name) == 1)
{
delete_name(s2);
}
else if (s1 == 'e')
{
printf("Bye.\n");
break;
}
else // No match.
printf("Wrong Input. %s %s\n", &s1, s2);
}
system("pause");
return 0;
}
语句recycle->name == x
检查两个指针是否指向 memory 中的同一个 object。 它不检查 memory 中的两个(不同)对象是否具有相同的内容。
利用
if (strcmp(recycle->name, x) == 0) { ...
检查相等的字符串内容。
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