爲什麼我在c中使用堆內存時出現運行時錯誤？

Question

我已經解決其中需要約瑟夫斯問題和一大組素數的問題....

這裏是我的代碼...

/* 
    josephus problem.uri judge:1030 
    author :: R_H_T 

*/ 


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

int count; 
//int *c = &count; 

typedef struct node{       // make a a linked list structure node with a number,next node and previous node 
    int number; 
    struct node *next; 
    struct node *previous; 
} node; 

node* create (int n){       //create nodes  
    node *nd = malloc(sizeof(node)); 
    nd->number = n; 
    nd->next = NULL; 
    nd->previous = NULL; 
    return nd; 
} 

void kill(node *n){        // set node.numbers = 0 
     n->number = 0; 
     //free(n); 

} 

node* next_node(node *n,int step){    // decide next node location by stepsize 
    if (step == 1) 
     { 
      //count = 0; 
      return n; 
     } 
    next_node(n->next,(step-1)); 
} 

void setvalue(int array_copy[], int i, int n) 
{ 
    int j,p; 

    for(j = 2; (i*j) <= n ; j++) 
    { 
     p = i*j; 
     array_copy[p] = 1; 
    } 
} 


int main(){ 
    //freopen("in.txt","r",stdin); 
    node *current,*update_next,*head,*temp; 
    int i,k,human_c,j=0,flag=0; 
    //scanf("%d",&testcase); // input testcases 

    //start prime number selection by algo -> Sieve of Eratosthenes 
    int n,l=0; 
    //scanf("%i",&n); 
    n=3502; 


    int prime_array[1000]; 
    int array[n]; 
    for (i = 1; i <= n; i++)  // initialize all value of the array to 0 
    { 
     array[i] = 0; 
    } 

    for(i = 2; i < n; i++) 
    { 
     setvalue(array,i,n);  // set value 0 to its muliple cases 
    } 
    for(i = 2; i <= n; i++) 
    { 
     if(array[i] == 0)  // find the value which is 0 and record it in an array naming prime_array[] 
     { 
      //printf("%i ",i); 
      prime_array[l] = i; 
      l++; 
     } 

    } 

    /*for (i = 0; i <= l ; i++) 
    { 
     printf("%i\n",prime_array[i]); 
    } */    
    // end prime number selection 

    for(k = 1;; k++) 
    { 
     //scanf("%i",&num_state); 

     scanf("%i",&human_c);  // scan the number of nodes 

     /*if(num_state < 13 || num_state > 100)     // limit is 13 <= N <= 100 
      return 1; 

     if(num_state == 13)         // state 13 gives 1...we knew that so we didn't compute 
     { 
      printf("%i\n",1); 
      continue; 
     }*/ 
     if(human_c == 0)          // a'0' input finishes it 
      return 0; 
     //count = 0; 


     node *first_node = create(1);   // create first node with node.number 1 

     node *last_node = create(human_c);  // create last node with node.number = number of people 

     node *a[human_c];      // decare a node type array 

     a[0]=NULL;        // keep a[0] out of it 
     a[1] = first_node;      // assign a[1] the first node 
     a[human_c] = last_node;     // assign a[number of people] the last node 

     a[1]->previous = last_node;    // link a[1] with previous 

     a[human_c]->next = first_node;   // link a[number of people] with the first node 


     for(i = 2; i < human_c;i++){   // create nodes from 2 to (number of people-1) 
      a[i] = create(i); 

     } 
     for(i= 2; i < human_c;i++){    //assign previous and next nodes for 2 to (number of people-1) 
      a[i]->next = a[i+1] ; 
      a[i]->previous = a[i-1]; 
     } 
     a[1]->next = a[2];      //link a[1] with next node a[2] 
     a[human_c]->previous = a[human_c-1]; //link (last node)a[number of people] with the previous a[number of people-1] 


     head = a[1];       //assign head or start position 
     flag = 0; 
     i = 0;        //set flag for the first node 

     do{ 

      if (flag == 0) 
       { 
        current = next_node(head,prime_array[i]);   // evaluate next position for head node or start node only saving in "current" node 
        temp = current->previous;     // keep the previous node for manipulation 
        temp->next = current->next;     // set node.next for the previous node to the next of the current node 
        update_next = current->next;    // keep the next node for manipulationk 
        update_next->previous = temp;    // set node.previous for the next node which is update_next to the address of the previous of the current node which is temp 
        //head->next = current -> next; 
        flag = 1; 
        i++; 
       } 
      else 
       { 
        current = next_node(update_next,prime_array[i]); // evaluate next position for rest of the nodes 
        temp = current->previous;     // keep the previous node for manipulation 
        temp->next = current->next;     // set node.next for the previous node to the next of the current node 
        update_next = current->next;    // keep the next node for manipulationk 
        update_next->previous = temp;    // set node.previous for the next node which is update_next to the address of the previous of the current node which is temp 
        //update_next->next = current->next; 
        i++; 
       } 


      //update_next->previous = current->previous; 

      kill(current);          // kill the newly found position 
      count++;           // take a record of the total kill 

      //node *current = next_node(update_next,step_c); 

     }while((human_c-count) > 1);       // keep the killing spree unit there is only one person left 

     for (i = 1; i <= human_c; i++) 
     { 
      if(a[i]->number)         // check if any node is alive which means anynode has a node.number higher than 0 
      { 
       //printf("Case %d: ",k); 
       printf("%i\n",a[i]->number); 

      } 
     } 

     for (i = 1; i <= human_c; i++){      // free the allocated space on heap 
      free(a[i]); 
     } 
     count = 0;            // set total kill to 0 as new testcase might start 

    } 
    return 0; 
} 

它爲值490，但它在491上給出了分割錯誤。爲什麼？

問題的環節是https://www.urionlinejudge.com.br/judge/en/problems/view/1032

Answer 1

next_node()不返回任何值，如果steps不等於1

你的編譯器可能會提醒你在這，順便說一句。

Answer 2

在main()和setvalue()索引超過array[]

void setvalue(int array_copy[], int i, int n) 
{ 
    ... 

    for(j = 2; (i*j) <= n ; j++) 
    { 
     p = i*j; 
     array_copy[p] = 1;  // ERROR: out of bounds when (i*j) == n 
    } 
} 

int main() 
{ 
    ... 

    n=3502; 
    ... 
    int array[n]; 
    ... 
    for (i = 1; i <= n; i++) 
    { 
     array[i] = 0;   // ERROR: out of bounds when i == n 
    } 

    for(i = 2; i < n; i++) 
    { 
     setvalue(array,i,n); 
    }   

    for(i = 2; i <= n; i++) 
    { 
     if(array[i] == 0)  // ERROR: out of bounds when i == n 
     ... 
    }