检查文件末尾的回车

Question

我有一个文本文件。 我必须检查以确保文件以回车符结束。 如果它没有以一个结尾，那么我想插入一个。 该文件现在具有正确的格式，我可以使用它进行进一步的解析。 它应该适用于Windows和Linux环境。

Answer 1

尝试这样的事情（未经测试）：

FILE *file = fopen(path, "r+");
char c;
fseek(file, -1, SEEK_END);
fread(&c, 1, 1, file);
if (c != '\r') { /* This will work on Win/Linux and also on a Mac */
  fseek(file, 0, SEEK_END);
  fprintf(path, "\r");
}
fclose(file);

注意：你确定你的意思是0x0D吗？ 在Linux中，行以0x0A（\\ n）结束，在Windows中以0x0D 0x0A（\\ r \\ n）组合结束。

Answer 2

看我准备了一个文件

    FILE *b = fopen("jigar.txt","w");
    fprintf(b,"jigar\r");
    fclose(b);

现在我再次打开该文件进行检查

 b = fopen("jigar.txt","r");
 char f;

转到文件末尾

while(fscanf (b, "%c", &f) != EOF);

前一个字节

  fseek( b,-1,1);

读那个字节

    fscanf(b,"%c",&f);

核实

    if(f == 13)  \\ here instead of 13 you can writr '\r'
        printf("\r is detected");
    else
          write \r to file...

Answer 3

#include <stdio.h>

void main()
{

    FILE *file = fopen("me.txt", "r+"); // A simple text file created using vim 

    char buffer[100] ;

    fseek(file, -2, SEEK_END); // Fetches the last 2 characters of the file 

    fread(buffer,1,2,file); // Read the last 2 characters into a buffer 

    printf("\n Character is %s",buffer); // Will print the entire contents of the buffer . So if the line ends with a "\n" we can expect a new line to be printed 

    //Since i am interested to know how the line feeds & Carriage returns are added to the end of the file , i try to print then both . I have run this code under Suse Linux and if i press enter key after the last line in the file i get two "\n" in the output . I confirmed this using GDB . I would like to run in a Windows environment and check how the behavior changes if any .
    printf(" --is %c",buffer[1]);
    printf(" --is %c",buffer[2]);

    if(buffer[1]=='\r' || buffer[2]=='\n')
    //take action 
    else 
    // take another action


    fclose(file);
}