Question

我链接列表中每个节点的值现在都等于'temp'，尽管我希望它们保持独立。当'temp'在while（1）循环的最后一次迭代中被分配给“STOP”时，所有其他值也被打印为“STOP”。

//*******************
//*  GEORGE TANGEN  *
//*      HW 9       *
//*******************

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

struct node{
   struct node *next;
   struct building *payload;
};

struct building{
    char *name;
    struct arc *list[];
};

struct arc{
    int weight;
    struct building *start;
    struct building *end;
};

int main(){

   struct node *head;
   struct node *trace;
   head = malloc( sizeof(struct node) );
   head->payload = malloc( sizeof(struct building) );
   head->payload->name = "Head";

   int k;
   trace = head;
   for(k=0;k<10;k++){
      trace->next = malloc( sizeof(struct node) );
      trace = trace->next;
      trace->payload = malloc( sizeof(struct building) );
      trace->payload->name = "hi";
   }

    FILE *f1;
    int i,j;
    char *op = {"hw9.data"};   
    f1 = fopen(op,"r");
    if(f1==NULL){
        printf("No File!");
        return 0;
    }
      trace = head;
      char temp[200];
      while(1){
         fscanf(f1, "%s", temp);
         if( (strcmp(temp, "STOP"))==0 ){
            break;
         }else{
            printf("INPUT: %s\n", temp);
            trace->payload->name = temp;
            printf("OUTPUT: %s\n", trace->payload->name);
            printf("HEAD: %s\n", head->payload->name);
            trace = trace->next;
         }
         printf("%s\n\n", temp);

      }

      trace = head;
      for(k = 0; k<10;k++){
         printf("OUTPUT: %s\n", trace->payload->name);
         trace = trace->next;
      }


   fclose(f1);

    return 0;   
}

Answer 1

每次在其上调用temp时，都会覆盖数组fscanf的内容，有两种方法。

首先，定义有效负载以保存字符数组，而不仅仅是指针

struct node{
    struct node *next;
    struct building *payload;
};

struct building{
    char name[256];
    struct arc *list[];
};

// trace->payload->name = temp; do not assign here, copy the string
strcpy(trace->payload->name, temp);

其次，保持struct不变，而是创建temp的新副本：

// trace->payload->name = temp; do not assign here, copy the string
trace->payload->name = strdup(temp);

如何将struct的char []赋值给文件的值，而不是指针？

1 个答案: