《C++捷徑教程》讀書筆記–Chapter 18–C++的I/O系統–12-15

//--《C++捷徑教程》讀書筆記--Chapter 18--C++的I/O系統
//--Chapter 18--C++的I/O系統
//--10/16/2006 Mon.
//--Chang'an University dormitory<#1-404>
//--xwlee

//寫入一個檔案--12
#include <iostream>
#include <fstream>
using namespace std;

int main()
{
 ofstream out("test");
 
 if(!out)
 {
  cout<<"cannot open file./n";
  return 1;
 }

 out<<10<<" "<<123.23<<endl;
 out<<"this is a short text file.";
 out.close();

 return 0;
}

 

//讀入一個檔案--13
#include <iostream>
#include <fstream>
using namespace std;

int main()
{
 char ch;
 int i;
 float f;
 char str[80];

 ifstream in("test");
 if(!in)
 {
  cout<<"cannot open file./n";
  return 1;
 }

 in>>i;
 in>>f;
 in>>ch;
 in>>str;

 cout<<i<<" "<<f<<" "<<ch<<endl;
 cout<<str<<endl;//讀入his

 return 0;
}

 

//get()輸出檔案內容--14
#include <iostream>
#include <fstream>
using namespace std;

int main(int argc, char *argv[])
{
 char ch;
 
 argc=2; argv[1]="test";

 if(argc!=2)
 {
  cout<<"Usage: PR <filename>/n";
  return 1;
 }

 ifstream in(argv[1], ios::in | ios::binary);
 if(!in)
 {
  cout<<"cannot open file./n";
  return 1;
 }

 while(in)
 {
  in.get(ch);
  if(in)
   cout<<ch;
 }

 in.close();

 return 0;
}

 

 //put()輸入檔案內容--15
#include <iostream>
#include <fstream>
using namespace std;

int main(int argc, char *argv[])
{
 char *p="hello there";

 ofstream out("test", ios::out|ios::binary);
 if(!out)
 {
  cout<<"cannot open file./n";
  return 1;
 }

 while(*p)
  out.put(*p++);

 return 0;
}