C，从文件中读取到结构 [英] C, reading from file into structure

问题描述

我一直在这个挣扎了几天，我想不通为什么它不工作。

我想用这样写的号码来读取文件编号：

  0 2012 1 1 2000.000000
0 2012 1 1 3000.000000
2012年1 1 1 4500.000000
 

我的结构：

 结构元素{        INT ID;
        INT标志;
        INT年;
        INT月;
        双量;        结构元素*接下来的;
};结构队列{
    结构元素*头;
    结构元素*尾;
    结构元素* HEAD2;
    结构元素*温度;
    结构元素* temph;    INT大小;
};
 

  

（HEAD2，温度和temph分拣结构使用）

和从文件中读取：

 无效read_str（结构队列*队列）{    FILE *读取;    字符文件名[40];
    INT温度;    的printf（类型中的文件\\ n名）;
    scanf函数（％S，＆安培;文件名）;
    读取=的fopen（文件名，R）;
    如果（阅读== NULL）{
        PERROR（错误）;
        返回1;
    }
    其他{
        而（！的feof（读取））{
            结构元素* N =（结构元素*）malloc的（的sizeof（结构件））;
            的fscanf（读，％D％D％LF，正与GT; ID，正＆gt;登录，正＆GT;同期，正＆GT;当月，正＆GT;金额）;
            正＆gt;接着= NULL;            如果（queue-＆GT;头== NULL）{
                queue-＆GT;头= N;
            }
            其他{
                queue-＆GT; tail-＆gt;接下来= N;
            }            queue-＆GT;尾= N;
            queue-＆GT;大小++;        }
    }
}
 

我可以更改数据看起来通过改变其写入功能的文件的方式，但我不认为这是问题。我猜我使用的malloc 以错误的方式。

解决方案

 的fscanf（读，％D％D％LF，正＆GT; ID，正＆gt;登录，正＆GT;同期，正＆GT ;当月，正＆GT;金额）;
 

的 scanf函数系列函数期望地址。更改的fscanf 行：

 的fscanf（读，％D％D％LF，＆安培; N-＆GT; ID，和放大器; N-＆gt;登录，和放大器; N-＆GT ;年，
    ＆安培; N-＆GT;当月，＆安培; N-＆GT;金额）;
 

---

侧面说明，这是一种严重误导行：

 其他{而（！的feof（读取））{
 

I've been struggling with this for days and I can't figure out why it doesn't work.

I'm trying to read numbers from file with numbers written like this:

0 2012 1 1 2000.000000
0 2012 1 1 3000.000000
1 2012 1 1 4500.000000

my structure:

struct element{

        int id;
        int sign;
        int year;
        int month;
        double amount;

        struct element *next;


};

struct queue{
    struct element *head;
    struct element *tail;
    struct element *head2; 
    struct element *temp;  
    struct element *temph; 

    int size;
};

(head2, temp and temph are used in sorting structure)

and reading from a file:

void read_str(struct queue *queue){

    FILE *reads;

    char filename[40];
    int temp;

    printf("Type in name of the file\n");
    scanf("%s",&filename);
    reads=fopen(filename, "r");
    if (reads==NULL) {
        perror("Error");
        return 1;
    }
    else { 
        while(!feof(reads)) {
            struct element *n= (struct element*)malloc(sizeof(struct element));             
            fscanf(reads,"%d %d %d %d %lf", n->id, n->sign, n->year, n->month, n->amount);                  
            n->next=NULL;                   

            if(queue->head ==NULL) {
                queue->head=n;
            }
            else {
                queue->tail->next=n;
            }

            queue->tail=n;
            queue->size++;                  

        }           
    }
}

I can change the way the data looks in a file by changing the function that writes it, but I don't think that's the problem. My guess I'm using malloc in a wrong way.

解决方案

fscanf(reads,"%d %d %d %d %lf", n->id, n->sign, n->year, n->month, n->amount);

The scanf family of functions expect addresses. Change the fscanf line to:

fscanf(reads,"%d %d %d %d %lf", &n->id, &n->sign, &n->year,
    &n->month, &n->amount);

---

Side note, this is a seriously misleading line:

else { while(!feof(reads)) {

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