EXC_BAD_ACCESS 与结构

Question

下面的代码创建一个结构数组，从1~9作为顶点，然后它接受顶点指向的其余部分。例如，如果有人输入 1 作为主顶点，他将允许为图输入多个节点。但是，我目前面临第三个 while 循环和最后一个循环的问题。对于这部分，它应该检测到 next 为 NULL 并退出，但它给我一个 EXC_BAD_ACCESS 错误。

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

struct node{
    int data;
    struct node* next;
};

int main(){
    struct node *G[10];
    for (int i = 1; i < 10; i++)
    {
        G[i]= malloc(sizeof(struct node));
        G[i]->data = i;
        G[i]->next = NULL;
        printf("%i\n", G[i]->data);
    }
    int input = 10;
    int vertixBeingModi=1;
    printf("Please enter your vertix you want to modify? \n");
    scanf("%i", &vertixBeingModi);
    while(vertixBeingModi != 0){
        while (input != 0){
            printf("Please enter the edges ? \n");
            scanf("%i", &input);
            struct node* cursor;
            struct node* newItem;
            cursor = G[vertixBeingModi];
            if (input == 0){
                break;
            }
            while(cursor->next != NULL )
            {
                cursor = cursor->next;
            }
            newItem = malloc(sizeof(struct node));
            cursor->next = newItem;
            newItem->data = input;
            cursor = G[vertixBeingModi];
        }
        printf("Please enter your vertix you want to modify? \n");
        scanf("%i", &vertixBeingModi);
        input = 1;
        if (vertixBeingModi == 0){
            break;
        }
    }
    int array[10];
    struct node* tempDegree;
    int counter = 0;
    for(int x = 1; x < 10; x++){
        tempDegree = G[x];
        if(tempDegree->next == NULL){
            continue;
        }else{
            while(tempDegree->next != NULL ){
                counter = counter + 1;
                tempDegree = tempDegree->next;
            }
            array[x] = counter;
            counter = 0;
        }
    }
    printf("%d\n", array[1]);
}

Answer 1

你只是忘了初始化 newItem->next:

while (cursor->next != NULL)
  {
    cursor = cursor->next;
  }
  newItem = malloc(sizeof(struct node));
  newItem->next = NULL;    // <<<<<<<<<<<< add this line
  cursor->next = newItem;
  newItem->data = input;
  cursor = G[vertixBeingModi];

EXC_BAD_ACCESS 与结构

EXC_BAD_ACCESS with struct

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