无法编译链表程序

Question

我一直在尝试修复我在编译此程序时遇到的几个错误，但似乎找不到任何解决方案。这些是在实际代码之后发生的以下错误。大多数错误都是“一元 * ”问题，尽管我认为这是使用它的正确方法。如果有人能指出我正确的方向，那将非常有帮助。

testReadLinkedList.c:13: warning: no semicolon at end of struct or union
testReadLinkedList.c: In function ‘insertListElement’:
testReadLinkedList.c:31: error: incompatible types in assignment
testReadLinkedList.c: In function ‘readFile’:
testReadLinkedList.c:43: warning: comparison between pointer and integer
testReadLinkedList.c: In function ‘countList’:
testReadLinkedList.c:51: error: invalid initializer
testReadLinkedList.c:54: error: invalid operands to binary !=
testReadLinkedList.c:56: error: invalid type argument of ‘unary *’
testReadLinkedList.c: In function ‘printList’:
testReadLinkedList.c:65: error: invalid initializer
testReadLinkedList.c:70: error: invalid type argument of ‘unary *’
testReadLinkedList.c:71: error: invalid type argument of ‘unary *’
testReadLinkedList.c:72: error: invalid type argument of ‘unary *’
testReadLinkedList.c:73: error: invalid type argument of ‘unary *’
testReadLinkedList.c:81: error: invalid type argument of ‘unary *’


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <float.h>

typedef struct LinkedListNode {
    int red;
    int green;
    int blue;
    char function[128];
    struct LinkedListNode* next
} LinkedListNode;

typedef struct {
    LinkedListNode* head;
} Linkedlist;

void initLinkedList(Linkedlist* listIn) {

    listIn = (Linkedlist*)malloc(sizeof(Linkedlist));
    (*listIn).head = NULL;
}

void insertListElement(Linkedlist* listIn, int redIn, int greenIn, int blueIn, char* functionIn) {
    LinkedListNode* newNode = (LinkedListNode*)malloc(sizeof(LinkedListNode));

    (*newNode).red = redIn;
    (*newNode).green = greenIn;
    (*newNode).blue = blueIn;
    (*newNode).function = functionIn;

    (*newNode).next = (*listIn).head;
    (*listIn).head = newNode;
}

void readFile(FILE* fileIn, Linkedlist* listIn) {

    char tempLine[128];
    int tempRed, tempGreen, tempBlue;
    char tempFunction[128];

    while(fgets(tempLine, 128, fileIn) != EOF) {
        sscanf(tempLine, "%d %d %d %[^\n]", &tempRed, &tempGreen, &tempBlue, tempFunction);
        insertListElement(listIn, tempRed, tempGreen, tempBlue, tempFunction);
    }

}

int countList(Linkedlist* listIn) {
    LinkedListNode currNode = (*listIn).head;
    int size = 0;

    while(currNode != NULL) {
        size++;
        currNode = (*currNode).next;
    }
    return size;
} 

void printList(Linkedlist* listIn) {

    int i, tempRed, tempGreen, tempBlue;
    char tempFunction[128];
    LinkedListNode currNode = (*listIn).head;
    int listSize = countList(listIn);

    for(i = 0;i < listSize; i++) {

        tempRed = (*currNode).red;
        tempGreen = (*currNode).green;
        tempBlue = (*currNode).blue;
        tempFunction = (*currNode).function;

        printf("Red: %d\n",tempRed);
        printf("Green: %d\n",tempGreen);
        printf("Green: %d\n",tempBlue);
        printf("Function: %s\n",tempFunction);
        print("t\n");

        currNode = (*currNode).next;
    }

} 

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

    FILE* f1;
    Linkedlist* list1;

    f1 = fopen(argv[1], "r");
    if(f1 == NULL) {
        printf("Error: could not open file");
    } else {
        initLinkedList(list1);
        readFile(f1, list1);        
    }

}

Answer 1

这里：

(*newNode).function = functionIn;

你需要将strcpy函数传入(*newNode).function，你不能简单地赋值给它。另外，在这一行：

while(fgets(tempLine, 128, fileIn) != EOF)

fgets 出错时不返回 EOF 而是返回 NULL，所以你需要这样做：

 while (fgets(tempLine, 128, fileIn))

在这一行：

LinkedListNode currNode = (*listIn).head;

head是指针，需要固定currNone的类型：

LinkedListNode *currNode = listIn->head;

最后，你需要改变你的初始化函数：

void initLinkedList(Linkedlist **listIn) {
  *listIn = (Linkedlist *)malloc(sizeof(Linkedlist));
  (*listIn)->head = NULL;
}

和电话：

initLinkedList(&list1);

Answer 2

1. struct LinkedListNode* next --> 缺少分号。

2. (*newNode).function = functionIn; 更改为strcpy(newNode->function,functionIn)。

3. char * fgets ( char * str, int num, FILE * stream ); 如果不成功（如果在尝试读取字符时遇到文件结尾），它将返回 NULL（不是 EOF）。

是一些提示。还有很多其他错误。您可能想再次阅读基本的 C 指针概念。

Answer 3

#include<iostream>
#include<conio.h>
#include<string.h>
using namespace std;
struct node
{
    int itemno;
    node *next;
};
node *temp=NULL,*top=NULL;
int e;

void push()
{
    temp=new node;
    temp->next=NULL;
    if(temp==NULL)
    {

    cout<<"stack overflow";
    return;
}

    cout<<"enter the itemno"<<endl;
    cin>>temp->itemno;
    //temp->itemno=e;
    if(top==NULL)
    {   
        top=temp;
}
    else
    {
        top=temp->next;
        top=temp;

    }
}
void pop()
{
    if(top==NULL)

        cout<<"stack underflow";


    else
    {
        top=temp;
            cout<<temp->itemno;
        top=top->next;


    }
        delete temp;
}
void display()
{
    if(top==NULL)
    {

    cout<<"stack underflow";
    return;
}
    else
    {
        temp=top;
        while(temp!=NULL)
        {
            cout<<temp->itemno;
            cout<<endl;
            temp=temp->next;
        }
    }
}
int main()
{   char choice1;
    int choice;
    while(1)
    {
        cout<<"menu"<<endl;
        cout<<"1.push"<<endl;
        cout<<"2.pop"<<endl;
        cout<<"e.displAY"<<endl;
        cout<<"4.exit"<<endl;
        cout<<"enter your choice"<<endl;
        cin>>choice;
        switch(choice)
        {
            case 1:{
                do
                { push();
                cout<<"enter y to add or n to cancel"<<endl;
                cin>>choice1;


                }while(choice1=='y');


            break;}
            case 2:{
                do
                {
                    cout<<"enter y to delete or n to cancel"<<endl;
                    cin>>choice1;
                    if(choice1=='y')
                    pop();
                }while(choice1=='y');


            break;}
            case 3:display();
            break;
            case 4:return 0;
            default:break;

        }

    }
        getch();
        return 0;


} can anybody point out the mistake in this.