c++中fstream类对文本文件的操作

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#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;}

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