fileaccess.cpp

适合初学者学习以及程序员回顾

// FileAccess.cpp

#include <iomanip>
#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::setw;

#include <cstring> 

#include <fstream>
using std::fstream;
using std::ofstream;
using std::ios;

// ---函数 Add_Txt() 的宣告--------
void  Add_Txt(char *);
// ---函数 WriteString () 的宣告---
void  WriteString (char *, char *, int Mode); 
// ---函数 WriteData () 的宣告-----
void  WriteData (char *,
       float *, int, int Mode=1); 

// ---主程式-----------------------
main ()
{
  const DataSize = 12;
  float Data [DataSize];
  char FileName[20]  = "SaveRecord";
  char* S1 = "A long time ago ...";
     
   Add_Txt(FileName);
       

      for (int i = 0; i < DataSize; i++)
         Data[i]= 3.8/float(1+i);

   WriteString (FileName, S1, 0); 
   WriteData   (FileName,
              Data, DataSize, 1);
}

// ---函数 Add_Txt() 的定义--------
void  Add_Txt(char *Fname)
// To add a .txt extension to a file name.
{
  int     i = 0;
   while ((Fname[i] != 0) && (Fname[i] != '.'))
      i++;
   strcpy (Fname+i,".txt");
}


// ---函数 WriteString () 的定义--------
void  WriteString (char *FileNameOut,
       char *String, int Mode) 
// mode:(1 = append, 0 = replace) 
{
  ofstream FileOutput;

   if (Mode)
      FileOutput.open( FileNameOut, ios::app);
   else    
      FileOutput.open( FileNameOut, ios::out);

  if (!FileOutput) 
     {cout<< "档案: " << FileNameOut
      << " 存档失败!" << endl; exit(1);}
   FileOutput << String;		             
   FileOutput.close();
   cout << "成功存于档案 "
        << FileNameOut << " 内." << endl;
}

// ---函数 WriteData () 的定义--------
void  WriteData (char *FileNameOut,
       float *Data, int Size, int Mode) 
// mode:(1 = append, 0 = replace) 
{
  ofstream FileOutput;

   if (Mode)
      FileOutput.open( FileNameOut, ios::app);
   else    
      FileOutput.open( FileNameOut, ios::out);

   if (!FileOutput) 
     {cout<< "档案: " << FileNameOut
      << " 存档失败!" << endl; exit(1);}
   FileOutput << "\n以下共有 " << Size 
              << " 组数据:"    << endl;
   for (int i = 0; i<Size; i++) 
      FileOutput << Data[i] << endl;		             

   FileOutput.close();
   cout << "成功存于档案 "
        << FileNameOut << " 内."<< endl;
}