合并文件的C程序找不到EOF，陷入无限循环！

Question

我在尝试运行我正在开发的这个程序时遇到一些问题...要求说我不允许使用排序功能...我自己做了一些事情...等等。

几乎，该程序编译但在执行后挂起...我猜它陷入了无限循环...但我似乎找不到它...:(

该程序读取已经存在的数据文件从最小到最大排序并将它们合并（排序）到第三个 .txt 文件中...

这两个文件是 Data1.txt 和 Data2.txt 包含：

Data1.txt

2
2
2
2

Data2.txt

1
3
5
7
9

merge.c

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


void sortData(FILE *fpData1, FILE *fpData2)
{

 int n, m; 
 FILE *fpMerge;


 fpMerge = fopen("Merge.txt", "w+");


 fscanf(fpData2, "%i", &n);
 fscanf(fpData1, "%i", &m);
 while(n != EOF || m != EOF)
 {

  if(n == EOF)
  {
   fscanf(fpData1, "%i", &m);

   while(m != EOF)
   {

    fprintf(fpMerge, "%i\n", m);
    fscanf(fpData1, "%i", &m);
   }
  }
  if(m == EOF)
  {
   fscanf(fpData2, "%i", &n);

   while(n != EOF)
   {

    fprintf(fpMerge, "%i\n", n);
    fscanf(fpData2, "%i", &n);
   }

  }

  if(n < m)
  {
   fprintf(fpMerge, "%i\n", n);
   fscanf(fpData2, "%i", &n);
  }
  if(n > m)
  {
   fprintf(fpMerge, "%i\n", m);
   fscanf(fpData1, "%i", &m);
  }
  if(n == m)
  {
   fprintf(fpMerge, "%i\n", n); 
   fprintf(fpMerge, "%i\n", m);
   fscanf(fpData2, "%i", &n);
   fscanf(fpData1, "%i", &m);

  }
 }

 fclose(fpMerge);
}

int main (void)
{
 FILE *fpData1;
 FILE *fpData2;


 fpData1 = fopen("Data1.txt", "r");
 if(fpData1 == NULL)
 {
  printf("There was an error opening the file...program terminating..\n");
  exit(1);
 }

 fpData2 = fopen("Data2.txt", "r");
 if(fpData2 == NULL)
 {
  printf("There was an error opening the file...program terminating..\n");
  exit(1);
 }



 sortData(fpData1, fpData2);


 fclose(fpData1);
 fclose(fpData2); 

 return 0;
}

Answer 1

您不想比较 n != EOF，而是比较 fscanf 的返回值：

int count_1;
count_1 = fscanf(fpData1, "%i", &m);
if (count_1 == EOF) // EOF (or error)
{
  // ...
}

fscanf 也会返回 EOF< /code> 出错。如果您需要区分 EOF 和错误条件，请使用 ferror(fpData1)，然后查找错误代码（存储在 errno 中）。

Answer 2

您对 EOF 的测试不太正确

void sortData(FILE *fpData1, FILE *fpData2)
{
    int data1;
    int data2; 
    FILE *fpMerge;

    fpMerge = fopen("Merge.txt", "w+");
    fscanf(fpData1, "%i", &data1);
    fscanf(fpData2, "%i", &data2);

    // While one file still has data        
    while(!feof(fpData1) && !feof(fpData2))
    {
        // Choose 1 file to test
        // Read from that file and put into merge file until either we
        // run out of data or the condition fails.
        if(data1 < data2)
        {
            do {fprintf(fpMerge, "%i\n", data1);}
            while ((fscanf(fpData1, "%i", &data1) != 0) && (data1 <= data2));
        }
        else
        {
            do {fprintf(fpMerge, "%i\n", data2);}
            while ((fscanf(fpData2, "%i", &data2) != 0) && (data2 <= data1));
        }
        // NOTE: if fscanf() returns 0 it has failed to read (EOF)
    }
    // One of the files has reached the EOF
    // Dump the other file.
    while(fscanf(fpData1, "%i", &data1) != 0) {fprintf(fpMerge, "%i\n", data1);}
    while(fscanf(fpData2, "%i", &data2) != 0) {fprintf(fpMerge, "%i\n", data2);}
}

Answer 3

EOF 不是一个字符。
EOF 不是整数。
任何文件中都不会包含 EOF（既不是 char 也不是 int）。

EOF 是一个条件。
文件要么处于该状态，要么（通常）不处于该状态。

您应该检查fscanf()的返回值以检测EOF或其他问题。