C语言读取文本文件

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

char* ReadFile(char *filename)
{
   char *buffer = NULL;
   int string_size,read_size;
   FILE *handler = fopen(filename,"r");

   if (handler)
   {
       //seek the last byte of the file
       fseek(handler,0,SEEK_END);
       //offset from the first to the last byte, or in other words, filesize
       string_size = ftell (handler);
       //go back to the start of the file
       rewind(handler);

       //allocate a string that can hold it all
       buffer = (char*) malloc (sizeof(char) * (string_size + 1) );
       //read it all in one operation
       read_size = fread(buffer,sizeof(char),string_size,handler);
       //fread doesnt set it so put a \0 in the last position
       //and buffer is now officialy a string
       buffer[string_size+1] = '\0';

       if (string_size != read_size) {
           //something went wrong, throw away the memory and set
           //the buffer to NULL
           free(buffer);
           buffer = NULL;
        }
    }

    return buffer;
}

int main() {
    char *string = ReadFile("yourfile.txt");
    if (string) {
        puts(string);
        free(string);
    }

    return 0;
}

#include   <stdio.h>  

long   filesize(FILE   *stream);  

int   main(void)  
{  
      FILE   *fptr;  

      stream   =   fopen( "MYFILE.TXT ",   "w+ ");  
      fprintf(fptr,   "This   is   a   test ");  
      printf( "Filesize   of   MYFILE.TXT   is   %ld   bytes\n ",   filesize(fptr));  
      fclose(fptr);  
      return   0;  
}  

long   filesize(FILE   *fptr)  
{  
      long   curpos,   length;  

      curpos   =   ftell(fptr);  
      fseek(fptr,   0L,   SEEK_END);  
      length   =   ftell(fptr);  
      fseek(fptr,   curpos,   SEEK_SET);  
      return   length;  
}   

 

#include "stdio.h"

int main()
{
 FILE *pf=NULL;   //文件指针

 int filelen=0;
 int i=0;
 char *buf;
 pf=fopen("D:\\test.txt","r");   //以只读方式打开文件
 if(pf==NULL)
 {
  return 0;
 }
 else
 {
  //获得文件长度

  fseek(pf,0,SEEK_END);   //文件指针移到末尾
  filelen=ftell(pf);   //获得文件当前指针位置，即为文件长度
  rewind(pf);   //将文件指针移到开头，准备读取

  buf=malloc(filelen+1);    //新建缓冲区，存储独处的数据
  //将缓冲区的数据设置为0
  for(i=0;i<filelen+1;i++)
   buf[i]=0;

  //读取文件
  fread(buf,filelen,1,pf);
  //关闭文件
  fclose(pf);
  //buf中即为要读出的数据

  printf("%s\n",buf);    //输出一下数据，你可以随便怎么用
  free(buf);    //最后记得要释放
 }
 return 1;
}

 

 

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