c++中fstream类对文本文件的操作

#include <iostream>
#include <string>
#include<fstream>
using namespace std;
//追加方式写文件
void writefile()
{
	fstream f("try.txt",ios::out|ios::app);
	if(!f){
    cout<<"File open error!\n";
    return;
	}
	f<<123<<" "<<456<<" "<<"my name is aa\n";
	f.close();
}
//读取文件
void readfile()
{
	fstream f("try.txt",ios::in);
	if(!f){
    cout<<"File open error!\n";
    return;
	}
	int a,b;
	char s[20];
	while(1)
	{
		a=0;b=0;
		s[0]=0;
	 f>>a>>b;
	 f.getline(s,20);
	 if(a==0) break;//循环读取数据，没有数据时退出
	 cout<<a<<" "<<b<<" "<<s<<endl;
	}
	f.close();

}
///复制文件二进制数据
void copybinary()
{
	ifstream fin("try1.txt",ios::in|ios::binary);
  if(!fin){
    cout<<"File open error!\n";
    return;
  }
  ofstream fout("try2.txt",ios::out|ios::binary);
  char c[1024];
  int count=0;
  while(!fin.eof())
  {
    fin.read(c,1024);
	count=fin.gcount();
	for(int i=0;i<count;i++)
	{
		c[i]=255-c[i];//字节取反，可以实现程序加密，让别人打不开，自己知道哪个字节少了多少，再还原
	}
    fout.write(c,count);
  }
  fin.close();
  fout.close();
  cout<<"Copy over!\n";
}

int main()
{

	/*writefile();
	readfile();*/
	copybinary();
	return 0;
}