文件输入输出的两种方法（常用第一种）

#include<iostream>#include<fstream>#include<iterator>using namespace std;int main(){ofstream fout1("test2.dat");ifstream fin1("test2.dat");if(!fout1){cout<<"can`topen fill .\n ";exit(1);//return 1;}fout1<<10<<" "<<123.456<<"\"this is a test fill.\"\n";fout1.close();//ifstream fin1("test2.dat",ios::in);if(!fin1){cout<<"can`t open fill .\n";exit(1);//return 1;}char* ptr;ptr=new char[30];int i=0;while(in!=eof){ptr[i]=*in;++i;++in;}/*char c;while(fin1>>c){ptr[i]=c;//cout<<c;++i;}*/cout<<ptr<<endl;delete []ptr;fin1.close();system("pause");return 0;}

#include <iostream>#include <fstream>using namespace std;int main(){ofstream fout1("test.dat",ios::out);if (!fout1){cout<<"cannot open fill.\n";exit(1);}fout1<<123<<" "<<hex<<endl;fout1<<"\"hello\"\n";    fout1.close();ifstream fin1("test.dat",ios::in);if(!fin1){cout<<"cannot open fill\n";exit(1);}char str[80];while(fin1){fin1.getline(str,80);cout<<str<<endl;}fin1.close();system("pause");return 0;}