Question

我首先说我是C的新手，现在，我很难解决一些非直观的错误。我已经尝试了很长一段时间才达成某种解决方案，但我总是走向死胡同。

我正在尝试构建一些用于通过动态链接列表插入和显示图形的函数。在编译时一切正常，但元素似乎没有很好地显示。实际上，就像下图中一样，只显示节点的第一个元素。

所以问题是导致这些错误和警告的原因以及如何删除它们？

enter image description here

如果你看看下面的代码，你会看到它有一些警告（我不知道它们出现的原因 - 我在Ubuntu中使用GNU编译器中的代码块）以及显示的问题图的元素。问题很可能出在display_graph函数中，但我无法实现。

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

typedef struct AdjListNode {
    int dest;
    struct LIST_NODE *next;
} LIST_NODE;

typedef struct AdjList {
    struct LIST_NODE *head;
} ADJACENCY_LIST;

LIST_NODE *create_node(int dest) {
    LIST_NODE *nod;
    if(dest<0) exit(0);
    nod = (LIST_NODE*)malloc(sizeof(LIST_NODE));
    if(nod==NULL) {
        printf("Problems at memory allocation!");
        exit(0);
    }
    nod->dest = dest;
    nod->next = NULL;
    return (LIST_NODE*)nod;
}

void display_graph(ADJACENCY_LIST *v) {
    int s, i;
    LIST_NODE *nod;
    s = sizeof(v);
    for(i=0;i<=s;i++) {
        nod = v[i].head;
        //citeste lista cu head in primul nod
        while(nod!=NULL) {
            printf("Data from node: %d \n", nod->dest);
            nod = nod->next;
        }
    }
}

int main()
{
    int n; //number of graph nodes
    int i; //just a counter
    int dest; dest = -1; //it's actually the "name" of the nodes. They  must all be positive so I started negative
    char c;
    ADJACENCY_LIST *t;
    printf("The number of nodes of the graph: ");
    scanf("%d", &n);
    t = (ADJACENCY_LIST*)malloc(n*sizeof(ADJACENCY_LIST));

    /* We make a loop for the nodes and each node has a while thru which I make the links */
    for(i=0;i<n;i++) {
        c = 'D'; // Initializing
        printf("Specify the links of the node %d with the others:\n", i);
        int contor; contor = 0;
        while(c=='D') {
            LIST_NODE *nod;
            printf("The link with node: ");
            scanf("%d%*c", &dest);
            if(dest>=0){
                 nod = create_node(dest);
                 if(contor==0) t[i].head = (LIST_NODE*)nod; // just make the first node a head node
            } else nod = NULL;
            //verificam daca vrem sa continuam
            printf("Do you want to link any other node to %d?(D to add, anything else STOP\n)", i);
            c = getchar();
            contor++; //increment counter
        }
        // inchidem lista
    }
   display_graph(t);
return 0;
}

任何帮助将不胜感激！

修改正如Christhofe（确认问题）和Abhishek Vasisht所指出的那样，向量v的大小实际上是指针的大小。

但是，仍有一些警告，我不知道为什么它们仍然出现......都是

|| === Build：Grafuri1中的Debug（编译器：GNU GCC编译器）=== | /home/marianpc/Anul_1/SDA/Grafuri1/main.c||在函数'display_graph'中： /home/marianpc/Anul_1/SDA/Grafuri1/main.c|33 |warning：从不兼容的指针类型分配 /home/marianpc/Anul_1/SDA/Grafuri1/main.c|38 |警告：从不兼容的指针类型分配 /home/marianpc/Anul_1/SDA/Grafuri1/main.c|28 |警告：未使用的变量's'[-Wunused-variable] | /home/marianpc/Anul_1/SDA/Grafuri1/main.c||函数'main'：| /home/marianpc/Anul_1/SDA/Grafuri1/main.c|71|warning：从不兼容的指针类型分配 /home/marianpc/Anul_1/SDA/Grafuri1/main.c|76 |warning：从不兼容的指针类型中分配 || ===构建完成：0个错误，5个警告（0分钟，0秒（秒））=== |

主要的是该程序现在正在运行。非常感谢！真有帮助!!

Answer 1

试试这个

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

typedef struct AdjListNode {
    int dest;
    struct LIST_NODE *next;
} LIST_NODE;

typedef struct AdjList {
    struct LIST_NODE *head;
} ADJACENCY_LIST;

LIST_NODE *create_node(int dest) {
    LIST_NODE *nod;
    if (dest < 0) exit(0);
    nod = (LIST_NODE*)malloc(sizeof(LIST_NODE));
    if (nod == NULL) {
        printf("Problems at memory allocation!");
        exit(0);
    }
    nod->dest = dest;
    nod->next = NULL;
    return (LIST_NODE*)nod;
}

void display_graph(ADJACENCY_LIST *v,int values) {
    int s, i;
    LIST_NODE *nod;

    for (i = 0; i < values; ++i)
    {
        nod = v[i].head;
        printf("Data from node: %d \n", i);
        while (nod != NULL)
        {
            printf("Data : %d \n", nod->dest);
            nod = nod->next;
        }
    }
}

int main()
{
    int n; //number of graph nodes
    int i; //just a counter
    int dest; dest = -1; //it's actually the "name" of the nodes. They  must all be positive so I started negative
    char* c = (char*)(malloc(sizeof(char)));

    ADJACENCY_LIST *t;
    LIST_NODE *last_added;

    printf("The number of nodes of the graph: ");
    scanf("%d", &n);
    t = (ADJACENCY_LIST*)calloc(n,sizeof(ADJACENCY_LIST));

    /* We make a loop for the nodes and each node has a while thru which I make the links */
    for (i = 0; i < n; i++) {
        //c = 'D'; // Initializing
        printf("Specify the links of the node %d with the others:\n", i);
        int contor; contor = 0;
        do {
            LIST_NODE *nod;
            printf("The link with node: ");
            scanf("%d", &dest);
            if (dest >= 0) {
                nod = create_node(dest);
                if (contor == 0)
                {
                    t[i].head = (LIST_NODE*)nod; // just make the first node a head node
                    last_added = nod;
                }
                else
                {
                    last_added->next = nod;
                    last_added = nod;
                }
            }
            //verificam daca vrem sa continuam
            printf("Do you want to link any other node to %d?(D to add, anything else STOP\n)", i);
            fflush(stdin);
            *c = getchar();
            contor++; //increment counter
        } while (*c == 'D');
    }
    display_graph(t,n);
    return 0;
}

Answer 2

以下代码编译干净，有效。

它无法为第一级指针列表中的每个条目提供节点列表。

您可以轻松添加该功能。

您还需要添加将每个malloc节点传递给free（）的功能特别是发生错误时

    private void Form1_Load(object sender, EventArgs e)
    {
        this.button1.Click += new System.EventHandler(this.button1_Click);
        this.button2.Click += new System.EventHandler(this.button1_Click);
        this.button3.Click += new System.EventHandler(this.button1_Click);

        // OR

        this.button1.Click += (s, a) => ShowMessageBox("Test1");
        this.button2.Click += (s, a) => ShowMessageBox("Test2");
        this.button3.Click += (s, a) => ShowMessageBox("Test3");
    }

    private void button1_Click(object sender, EventArgs e)
    {
        MessageBox.Show("Hello Event World");
    }

    private void ShowMessageBox(string message)
    {
        MessageBox.Show(message);
    }

带有动态链接列表的图表表示

2 个答案: