故障排除編譯時間循環鏈表錯誤

Question

好了，所以我得到這些錯誤在用gcc編譯：

prelab6.h: In function âinsertHeadCircularâ: 
prelab6.h:45: error: incompatible types in assignment 
prelab6.h:46: error: incompatible types in assignment 
prelab6.c: At top level: 
prelab6.c:41: warning: data definition has no type or storage class 
prelab6.c:41: warning: parameter names (without types) in function declaration 
prelab6.c:41: error: conflicting types for âprintInOrderâ 
prelab6.h:81: error: previous definition of âprintInOrderâ was here 
prelab6.c:42: warning: data definition has no type or storage class 
prelab6.c:42: warning: parameter names (without types) in function declaration 
prelab6.c:42: error: conflicting types for âprintReverseâ 
prelab6.h:112: error: previous definition of âprintReverseâ was here 

我已經試了又試，但無濟於事修正這些錯誤。感謝任何和所有的幫助。

這是我的.c文件：

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include "my.h" 

int main (int argc, char **argv) 
{ 

char firstname[100]; 
char lastname[100]; 
int monthsEmployed; 

FILE *fptr; 
fptr = fopen(argv[1], "r"); 

if (fptr == NULL) 
    printf ("Incorrect file reading!"); 

if (argc != 2) 
    printf ("Incorrect number of arguments!"); 


employeeInfo *insert; 
insert = malloc(sizeof(employeeInfo)); 
employeeList *head; 
head = NULL; 


while(!feof(fptr)) 
{ 
    fscanf (fptr, "%100s %100s %d", firstname, lastname, &monthsEmployed); 

    strcpy(insert->firstname, firstname); 
    strcpy(insert->lastname, lastname); 
    insert->monthsEmployed = monthsEmployed; 

    head = insertHeadCircular(head, insert); 
} 
} 

printInOrder(head); // display the linked list 
printReverse(head); // display the linked list in reverse 

我的.h文件中（注意事物被註釋掉了，因爲我嘗試不同的事情沒有結果）：

typedef struct employeeInfo{ 
     char firstname[100]; 
     char lastname[100]; 
     int monthsEmployed; 
}employeeInfo; 

//Struct containing pointers to the next and previous used to make a circular linked list 
typedef struct list{ 
       employeeInfo emp; 
       struct list *next; 
       struct list *previous; 
}employeeList; 

employeeList *insertHeadCircular(employeeList *head, employeeInfo *emp); 
void printInOrder(employeeList head); 
void printReverse(employeeList head); 

employeeList *insertHeadCircular(employeeList *head, employeeInfo *emp) 
{ 
    employeeList *theprevious = head; 
    employeeList *current; 
    employeeList *thenext = head; 
    current = malloc(sizeof(employeeList)); 
    employeeInfo *employee; 

    if(thenext==NULL) 
    { 
     current->next = current; 
     current->previous = current; 
    } 

    else 
    { 
     current->next = thenext; 
     thenext->previous = current; 

     while(theprevious->next != thenext) 
     { 
      theprevious = theprevious->next; 
     } 
     current->previous = theprevious; 
     theprevious->next = current; 
    } 

    current->emp = (employeeInfo *)malloc(sizeof(employeeInfo)); 
    employee = current->emp; 
    employee = malloc(sizeof(employeeInfo)); 
    strcpy(employee->firstname, emp->firstname); 
    strcpy(employee->lastname, emp->lastname); 
    employee->monthsEmployed = emp->monthsEmployed; 

    /* 
    employeeList *newcell, *first = head; 

    if(head == NULL) 
    { 
     newcell = (struct list *)malloc(sizeof(struct list)); 
     strcpy(newcell->firstname, emp->firstname); 
     strcpy(newcell->lastname, emp->lastname); 
     newcell->monthsEmployed = emp->monthsEmployed; 
     return newcell; 
    } 

    while(head->next != first) 
    { 
     head = head->next; 
    } 

    newcell = (struct list *)malloc(sizeof(struct list)); 
    head->next = newcell; 
    strcpy(newcell->firstname, emp->firstname); 
    strcpy(newcell->lastname, emp->lastname); 
    newcell->monthsEmployed = emp->monthsEmployed; 
    newcell->next = first; 
    */ 
return current; 
} 


void printInOrder(employeeList head) 
{ 
    /*employeeInfo *first = head; 

    if (head == NULL) 
     { 
     printf("The circularly linked list is empty!\n"); 
     return; 
     } 

     do 
     { 

     printf("%s %s %d\n", emp.firstname, emp.lastname, head.monthsEmployed); 

     head = head->next; 
     } while(head != first); 
*/ 
    /*employeeInfo current = head; 
    employeeInfo start = head; 
    int loop = 0; 
    printf("--------------\n"); 
    while(current != start || loop==0) 
    { 
    loop++; 
    printf("Employee: %s %s\nMonths Employed: %d", current->firstname, current->lastname, current->monthsEmployed); 
    printf("--------------\n"); 
    current=current->next; 
    }*/ 
} 

void printReverse(employeeList head) 
{/* 
    employeeList current = head 
    employeeInfo start = head 
    int theloop=0; 
    printf("--------------\n"); 
    while(current! = start || loop==0) 
    { 
    loop++; 
    printf("Employee: %s %s\nMonths Employed: %d", current->firstname, current->lastname, current->monthsEmployed); 
    printf("--------------\n"); 
    current=current->previous; 
    }*/ 
} 

編輯好的程序

錯誤：

file.c: In function âmainâ: 
file.c:37: error: incompatible type for argument 2 of âinsertHeadCircularâ 

的.C：

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include "file.h" 

int main (int argc, char **argv) 
{ 

char firstname[100]; 
char lastname[100]; 
int monthsEmployed; 

FILE *fptr; 
fptr = fopen(argv[1], "r"); 

if (fptr == NULL) 
    printf ("Incorrect file reading!"); 

if (argc != 2) 
    printf ("Incorrect number of arguments!"); 


employeeInfo *insert; 
insert = malloc(sizeof(employeeInfo)); 
employeeList *head; 
head = NULL; 


while(!feof(fptr)) 
{ 
    fscanf (fptr, "%100s %100s %d", firstname, lastname, &monthsEmployed); 

    strcpy(insert->firstname, firstname); 
    strcpy(insert->lastname, lastname); 
    insert->monthsEmployed = monthsEmployed; 

    head = insertHeadCircular(head, insert); 
} 

printInOrder(head); // display the linked list 
printReverse(head); // display the linked list in reverse 
} 

的.H：

typedef struct employeeInfo{ 
    char firstname[100]; 
    char lastname[100]; 
    int monthsEmployed; 
}employeeInfo; 

typedef struct list{ 
    employeeInfo emp; 
    struct list *next; 
    struct list *previous; 
}employeeList; 
    typedef employeeList *listnode; 

employeeList *insertHeadCircular(employeeList *head, employeeInfo emp); 
void printInOrder(employeeList *head); 
void printReverse(employeeList *head); 



employeeList *insertHeadCircular(employeeList *head, employeeInfo emp) 
{ 
    listnode newPtr; 
    listnode firstPtr; 
    listnode tempPtr; 

    newPtr = (employeeList *)malloc(sizeof(employeeList)); 

    strcpy(newPtr->emp.firstname, emp.firstname); 
    strcpy(newPtr->emp.lastname, emp.lastname); 
    newPtr->emp.monthsEmployed = emp.monthsEmployed; 

    if(head == NULL) 
    { 
     newPtr->next = newPtr; 
     newPtr->previous = newPtr; 
     head = newPtr; 
     firstPtr = newPtr; 

    } 
    else 
    { 
     tempPtr = firstPtr; 
     newPtr->next = tempPtr; 
     tempPtr->previous = newPtr; 

     newPtr->previous = head; 
     head->next = newPtr; 
     firstPtr = newPtr; 
    } 
    return head; 
} 
void printInOrder(employeeList *head) 
{ 
     listnode currentPtr = head; 
     do 
    { 
      printf("%s %s %d\n",currentPtr->emp.firstname, currentPtr->emp.lastname, currentPtr->emp.monthsEmployed); 
     currentPtr= currentPtr->previous; 
    } 
    while(currentPtr !=head); 
} 
void printReverse(employeeList *head) 
{ 
     listnode currentPtr = head->next; 
     do   
    { 
     printf("%s %s %d\n",currentPtr->emp.firstname, currentPtr->emp.lastname, currentPtr->emp.monthsEmployed); 
     currentPtr = currentPtr->next; 
    } 
    while(currentPtr != head->next);   
} 

Answer 1

在你insertHeadCircular()功能，你對待的employeeList的emp成員，就好像是一個employeeInfo *。例如，你聲明：

employeeInfo *employee; 

但後來做到這一點：

employee = current->emp; 

但是，你employeeList類型包含的employeeInfo，不是指針的實例之一：

typedef struct employeeInfo{ 
     char firstname[100]; 
     char lastname[100]; 
     int monthsEmployed; 
}employeeInfo; 
/* ... */ 
typedef struct list{ 
       employeeInfo emp; /* see? Not a pointer. */ 
       struct list *next; 
       struct list *previous; 
}employeeList; 

所以基本上你需要糾正你的代碼，這樣你就可以停止爲一個指針分配一個結構，而是將的地址分配給指針的結構。

最有可能你的printInOrder()和printReverse()功能應採取employeeList *參數，而不是那些employeeList，以及...你應該檢查你使用它們，以確保你不要混淆這兩個任意位置的代碼。

在頭文件以外的地方定義函數也是一個好主意，例如在單獨的.c源文件中。頭文件應該只包含其他源文件可能需要的函數原型，宏和其他聲明;您不需要那裏的函數體，因爲鏈接程序可以在從其他源創建的目標文件中找到它們。在這樣的頭文件中定義函數會在頭文件由多個文件編輯時導致無窮無盡的頭痛。

---

你與你的更新代碼得到的錯誤，file.c:37: error: incompatible type for argument 2 of âinsertHeadCircularâ是指出你傳遞給insertHeadCircular()參數的類型是不是你在其聲明中給出的類型 - 這是事實。你已經聲明和定義函數採取employeeInfo作爲第二個參數：

employeeList *insertHeadCircular(employeeList *head, employeeInfo emp) 

...但在main()你傳遞一個指針來代替：

employeeInfo *insert; 
... 
    head = insertHeadCircular(head, insert); 

所以你需要改變一個或另一個。從main調用函數時取消引用insert，或者改變insertHeadCircular()以取代指針（並相應地更新主體）。後者可能更好，因爲它可以避免在調用函數時將整個結構複製到堆棧中。

一些其他的事情要指出：

你真的應該檢查從scanf()在循環中main()回報。它會讓你知道是否所有的字段都是實際讀取的;現在，如果它們不是，你的程序就會繼續處理已有變量的任何垃圾（例如可能在前面的迭代中讀取的任何垃圾）。檢查其他返回值（如從malloc()返回）也是一個好主意，但在這種情況下，scanf()回報尤其重要。

你也沒有在你的程序結束時免費獲得insert;當你的程序退出時，操作系統將（幾乎可以肯定）清理它，但是當你完成它時，你可以自己做這個練習。不過，您使用它的方式並不是真的需要動態分配它;你可以剛剛宣佈一個employeeInfo並採取了其地址（無論以任何方式，但是）。