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我正在製作員工鏈接列表。做所有常見的事情，添加，搜索和更新。我試圖讓刪除功能正常工作，但在Node被刪除之後，我無法打印鏈接列表來查看。以下是完整的代碼以及錯誤消息。感謝您抽時間閱讀。在刪除節點後打印結構鏈表的錯誤
LinkedList.exe中的0x0FA4FB53（msvcr120d.dll）未處理的異常：0xC0000005：訪問衝突讀取位置0xFEEEFEEE。
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define ID_LENGTH 25
#define NAME_LENGTH 25
#define address_LENGTH 25
#define department_LENGTH 25
#define joinDate_LENGTH 25
#define email_LENGTH 30
int mymenu;
//Create employee Structure
typedef struct employee{
char* ID;
char* name;
char* department;
char* address;
char* joinDate;
double salary;
char* email;
struct employee *next;
}employee;
//Declare Function Prototypes
int login();
int Menu();
void Add(struct employee *head);
void search(struct employee *head, char*);
void update(struct employee *head, char*);
void outputList();
struct employee* searchForEmployee(char*);
employee* new_employee(char*, char*, char*, char*, char*, double, char*);
employee* insert_by_employee(employee*, employee*);
void removeEmployee(char *);
void print_list(employee*); // prints out the LinkedList
employee* head = NULL;
employee* tail = NULL;
employee* temp = NULL;
employee* current = NULL;
//this stores the employee that comes before the employee that is found by the searchforEmployee
struct employee *empBeforeEmptoDelete = NULL;
int main() {
int num = 0;
int MenuChoice = 0;
Menu();
FILE *in;
char* ID = (char*)malloc(sizeof(char*) * ID_LENGTH);
char* name = (char*)malloc(sizeof(char*) * NAME_LENGTH);
char* department = (char*)malloc(sizeof(char*) * department_LENGTH);
char* address = (char*)malloc(sizeof(char*) * address_LENGTH);
char* joinDate = (char*)malloc(sizeof(char*) * joinDate_LENGTH);
double salary = 0;
char* email = (char*)malloc(sizeof(char*) * email_LENGTH);
if ((in = fopen("Employees.txt", "r")) == NULL) //Did the file successfully open?
{
printf("The input file failed to open.\n");
printf("Program cannot continue. Exiting. . .\n");
return 1; //Exit Program
}
while (!feof(in)) //Check for file end
{
//Read first data value to kickstart.
if (fscanf(in, "%s %s %s %s %s %lf %s", ID, name, department, address, joinDate, &salary, email) == EOF) {
break;
}
employee* hold = new_employee(ID, name, department, address, joinDate, salary, email);
head = insert_by_employee(head, hold);
}
//3. ------Print the new List------
//print_list(head);
do
{
switch (MenuChoice = Menu())
{
case 1:
{
Add(head);
break;
}
case 2:
{
char text[10];
printf("Enter the text to search for :");
scanf("%s", text);
//search(head, text);
searchForEmployee(text);
break;
}
case 3:
{
char text[10];
printf("Enter the ID to update for :");
scanf("%s", text);
update(head, text);
break;
}
case 4:
{
outputList();
char text[10];
printf("Enter the ID to remove :");
scanf("%s", text);
removeEmployee(text);
outputList();
break;
}
case 5:
{
print_list(head);
break;
}
case 6:
{
break;
}
case 7:
{
break;
}
case 8:
{
exit(0);
break;
}
default:
{
printf("\nInvalid Selection");
break;
}
}
} while (MenuChoice < 8);
system("Pause");
printf("\n\n\n");
return 1; //Exit Success
}
employee* new_employee(char* id, char* name, char* department, char* address, char* joinDate, double salary, char* email) {
//Create new employee and malloc space
employee* new = (employee*)malloc(sizeof(struct employee));
new->ID = (char*)malloc(sizeof(char) * ID_LENGTH);
new->name = (char*)malloc(sizeof(char) * NAME_LENGTH);
new->department = (char*)malloc(sizeof(char) * department_LENGTH);
new->address = (char*)malloc(sizeof(char) * address_LENGTH);
new->joinDate = (char*)malloc(sizeof(char) * joinDate_LENGTH);
new->email = (char*)malloc(sizeof(char) * email_LENGTH);
//Set data
strcpy(new->ID, id);
strcpy(new->name, name);
strcpy(new->department, department);
strcpy(new->address, address);
strcpy(new->joinDate, joinDate);
new->salary = salary;
strcpy(new->email, email);
//Retun a pointer to the node
return new;
}
//Inserts new node into an alphabetically sorted linked list.
employee* insert_by_employee(employee* head, employee* new)
{
employee* current = NULL;
current = head;
if (current == NULL || strcmp(current->department, new->department) > 0)
{
new->next = current;
return new;
}
else {
while (current->next != NULL && strcmp(current->next->department, new->department) < 0)
{
current = current->next;
}
}
new->next = current->next;
current->next = new;
return head;
}
struct employee* searchForEmployee(char* id){
struct employee *empIterator = head;
char i[] = "Employee ID";
char n[] = "Name";
char a[] = "Address";
char d[] = "Department";
char jd[] = "Join Date";
char s[] = "Salary";
char em[] = "Email";
while (empIterator != NULL){
int isEqual = strcmp(empIterator->ID, id);//if the passed in ID is equla to the ID of the node then isEqual will ring true
if (!isEqual){
printf("Employee Found\n");
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);//header formatting
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", empIterator->ID, empIterator->name, empIterator->address, empIterator->department, empIterator->joinDate, empIterator->salary, empIterator->email);
//printing out the current node which is the desired employee
printf("-----------------------------------------------------------------------------------------------------------------------------------------------------\n");
return empIterator;
}
empBeforeEmptoDelete = empIterator->next;
empIterator = empIterator->next;
}
printf("%s was not found\n\n", id);
return NULL;
}
void print_list(employee* head)
{
employee* current;
current = head;
char i[] = "Employee ID";
char n[] = "Name";
char a[] = "Address";
char d[] = "Department";
char jd[] = "Join Date";
char s[] = "Salary";
char em[] = "Email";
//Header
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);
printf("--------------------------------------------------------------------------------------------------------------------------------------------\n");
while (current != NULL)
{
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", current->ID, current->name, current->address, current->department, current->joinDate, current->salary, current->email);
current = current->next;
}
printf("-------------------------------------------------------------------------------------------------------------------------------------------\n");
return;
}
int login()
{
char username[7];
char password[7];
printf("\nPlease enter your Username: ");
scanf("%s", username);
printf("\nPlease enter your Password: ");
scanf("%s", password);
struct login{
char name[7];
char password[7];
};
struct login details[3];
fflush(stdin);
FILE *file;
file = fopen("login.txt", "r");
if (file == NULL){
printf("Can not open the file\n");
exit(-1);
}
fflush(stdin);
for (int i = 0; i < 3; i++){
fscanf(file, "%s %s\n", details[i].name, details[i].password);
}
for (int i = 0; i < 3; i++){
if ((strcmp(details[i].name, username) == 0) && (strcmp(details[i].password, password) == 0))
{
printf("\nWelcome ");
Menu();
}
fflush(stdin);
}
}
int Menu()
{
int Choice = 0;
do{
printf("1. Add\n");
printf("2. Show\n");
printf("3. Update\n");
printf("4. Delete\n"); // Write a Function for this
printf("5. Departments\n");
printf("6. Employee Report\n");
printf("7. \n");
printf("8. Exit\n\n\n\t\tSELECTION = ");
fflush(stdin);
scanf("%d", &Choice);
fflush(stdin);
} while (Choice < 0 || Choice > 8);
return(Choice);
}
void Add()
{
char* ID = (char*)malloc(sizeof(char*) * ID_LENGTH);
char* name = (char*)malloc(sizeof(char*) * NAME_LENGTH);
char* department = (char*)malloc(sizeof(char*) * department_LENGTH);
char* address = (char*)malloc(sizeof(char*) * address_LENGTH);
char* joinDate = (char*)malloc(sizeof(char*) * joinDate_LENGTH);
double salary = 0;
char* email = (char*)malloc(sizeof(char*) * email_LENGTH);
printf("\nEnter the ID : ");
scanf("%s", ID);
printf("\nEnter the new employee name : ");
scanf("%s", name);
printf("\nEnter their address : ");
scanf("%s", address);
printf("\nEnter their department : ");
scanf("%s", department);
printf("\nEnter their start date : ");
scanf("%s", joinDate);
printf("\nEnter their salary : ");
scanf("%lf", &salary);
printf("\nEnter their email : ");
scanf("%s", email);
employee* hold = new_employee(ID, name, department, address, joinDate, salary, email);
head = insert_by_employee(head, hold);
}
void search(struct employee *head, char *crit)//This function takes in the head pointer and a character array pointer
{
int choice;//menu choice tracker
//arrays to hold the header heads
char i[] = "Employee ID";
char n[] = "Name";
char a[] = "Address";
char d[] = "Department";
char jd[] = "Join Date";
char s[] = "Salary";
char em[] = "Email";
//sub menu to filter by ID and Name searches
printf("\nSearch by ");
printf("\n1 : ID");
printf("\n2 : Name\n");
scanf("%d", &choice);
//if the user wants to search by ID
if (choice == 1){
while (head != NULL)
{
//compare the ID to the criteria. If its the same then execute this if
if ((strcmp(head->ID, crit) == 0))
{
//print that we found the employee
printf("Employee Found\n");
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);//header formatting
printf("----------------------------------------------------------------------------------------------------------------------------------------------------\n");
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", head->ID, head->name, head->address, head->department, head->joinDate, head->salary, head->email);
//printing out the current node which is the desired employee
printf("-----------------------------------------------------------------------------------------------------------------------------------------------------\n");
return;
}
head = head->next;//increments the node until we get to the end of the Linked List
}
printf("Employee not found\n");//Else there is no Employee with an ID of the entered criteria
}
//if the user wants to search by Name
else if (choice == 2){
while (head != NULL)
{
//compare the Name to the criteria. If its the same then execute this if
if ((strcmp(head->name, crit) == 0))
{
//print that we found the employee
printf("Employee Found\n");
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);//header formatting
printf("----------------------------------------------------------------------------------------------------------------------------------------------------\n");
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", head->ID, head->name, head->address, head->department, head->joinDate, head->salary, head->email);
//printing out the current node which is the desired employee
printf("----------------------------------------------------------------------------------------------------------------------------------------------------\n");
return;
}
head = head->next;//increments the node until we get to the end of the Linked List
}
printf("Employee not found\n");//Else there is no Employee with an Name of the entered criteria
}
else
printf("Bad input");//Otherwise the user entered a choice out of the range of our handled input
}
void update(struct employee *head, char *crit)//This function takes in the head pointer and a character array pointer
{
//arrays to hold the header heads
char i[] = "Employee ID";
char n[] = "Name";
char a[] = "Address";
char d[] = "Department";
char jd[] = "Join Date";
char s[] = "Salary";
char em[] = "Email";
char id[25];
char name[25];
char address[25];
char department[25];
char joinDate[25];
double salary;
char email[25];
//if the user wants to search by ID
while (head != NULL)
{
//compare the ID to the criteria. If its the same then execute this if
if ((strcmp(head->ID, crit) == 0))
{
//print that we found the employee
printf("Employee Found\n");
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);//header formatting
printf("----------------------------------------------------------------------------------------------------------------------------------------------------\n");
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", head->ID, head->name, head->address, head->department, head->joinDate, head->salary, head->email);
//printing out the current node which is the desired employee
printf("-----------------------------------------------------------------------------------------------------------------------------------------------------\n");
printf("\nEnter the ID : ");
scanf("%s", id);
printf("\nEnter the new employee name : ");
scanf("%s", name);
printf("\nEnter their address : ");
scanf("%s", address);
printf("\nEnter their department : ");
scanf("%s", department);
printf("\nEnter their start date : ");
scanf("%s", joinDate);
printf("\nEnter their salary : ");
scanf("%lf", &salary);
printf("\nEnter their email : ");
scanf("%s", email);
strcpy(head->ID, id);
strcpy(head->name, name);
strcpy(head->department, department);
strcpy(head->address, address);
strcpy(head->joinDate, joinDate);
head->salary = salary;
strcpy(head->email, email);
printf("Employee Found\n");
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);//header formatting
printf("----------------------------------------------------------------------------------------------------------------------------------------------------\n");
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", head->ID, head->name, head->address, head->department, head->joinDate, head->salary, head->email);
//printing out the current node which is the desired employee
printf("-----------------------------------------------------------------------------------------------------------------------------------------------------\n");
return;
}
head = head->next;//increments the node until we get to the end of the Linked List
}
printf("Employee not found\n");//Else there is no Employee with an ID of the entered criteria
}
void outputList(){
char i[] = "Employee ID";
char n[] = "Name";
char a[] = "Address";
char d[] = "Department";
char jd[] = "Join Date";
char s[] = "Salary";
char em[] = "Email";
struct employee * employees = head;
printf("Employees Entered\n\n");
while (employees != NULL){
printf("Employee Found\n");
printf("\n\n|%15s | %15s | %15s | %15s | %15s| %15s | %15s|\n", i, n, a, d, jd, s, em);//header formatting
printf("|%15s | %15s | %15s |%15s | %15s | %15.2lf| %25s\n", employees->ID, employees->name, employees->address, employees->department, employees->joinDate, employees->salary, employees->email);
printf("-----------------------------------------------------------------------------------------------------------------------------------------------------\n");
employees = employees->next;
}
}
void removeEmployee(char* empID){
struct employee* empToDelete = NULL;
empToDelete = searchForEmployee(empID);
if (empToDelete != NULL){
printf("%s was deleted\n\n", empID);
if (empToDelete == head){
head = empToDelete->next;
}
else{
empBeforeEmptoDelete->next = empToDelete->next;
}
free(empToDelete);
}
else{
printf("%s was not found", empID);
}
}