C++中关于读取文件的疑惑。。。
定义一个类
class Person //基本资料
{
protected:
char Pname[20]; //姓名
int Pyear; //出生年月
int Pmonth;
char Psex; //性别
int Pday;
char Paddr[20]; //住址
long int Pphone; //联系电话
public:
Person(string name= "none ", char sex= '? ',int y=0, int m=0,int d=0,string addr= "none ",long int phone=0);
friend std::ostream & operator < <(std::ostream &os,const Person &p) ;
};
类实现
Person::Person(string name, char sex, int y , int m, int d,string addr, long phone)
{
strncpy(Pname,name.c_str(),19);
Pname[19]= '0 ';
Psex=sex;
Pyear=y;
Pmonth=m;
Pday=d;
strncpy(Paddr,addr.c_str(),19);
Paddr[19]= '0 ';
Pphone=phone;
}
std::ostream & operator < <(std::ostream &os, const Person &p)
{
os < < "\t姓名: " < <p.Pname;
os < < "\t性别: " < <p.Psex < <endl;
os < < "联系电话: " < <p.Pphone;
os < < "出生年月: " < <p.Pyear < < "/ " < <p.Pmonth < < "/ " < <p.Pday;
os < < "\t住址: " < <p.Paddr < <endl;
return os;
}
主函数：
int main()
{
Person s[3]=
{
Person( "zmx ", 'm ',1987,06,8, "fuzhou ",5210269),
Person( "zhl ", 'f ',1988,02,10, "quanzhou ",5239448),
Person( "zll ", 'm ',1988,02,10, "quanfu ",110)
};
ofstream OutFile;
OutFile.open( "saleman.dat ",ios::app|ios::binary);
for(int i=0;i <3;++i)
OutFile.write((char *)&s[i],sizeof(Person));
OutFile.close();
ifstream InFile;
InFile.open( "saleman.dat ",ios::binary);
Person a[3];
for(int i=0;i <3;++i)
{
InFile.seekg(i*sizeof(Person),ios::beg);
InFile.read((char *)&a[i],sizeof(Person));
cout < <a[i];
}
InFile.close();
system( "pause ");
return 0;
}
第一次运行的时候没有错，第二次运行的时候将一些参数修改一下就出错了
第二次运行时候的参数
int main()
{
Person s[3]=
{
Person( "zzz ", 'm ',1987,06,8, "fuzhou ",5210269),
Person( "zhl ", 'f ',1988,02,10, "quanzhou ",5239448),
Person( "zll ", 'm ',1988,02,10, "quanfu ",110)
};
ofstream OutFile;
OutFile.open( "saleman.dat ",ios::app|ios::binary);
for(int i=0;i <3;++i)
OutFile.write((char *)&s[i],sizeof(Person));
OutFile.close();
ifstream InFile;
InFile.open( "saleman.dat ",ios::binary);
Person a[3];
for(int i=0;i <6;++i)
{
InFile.seekg(i*sizeof(Person),ios::beg);
InFile.read((char *)&a[i],sizeof(Person));
cout < <a[i];
}
InFile.close();
system( "pause ");
return 0;
}
请问如何才能在文件末端添加数据而且读取数据的时候不会出现错误？？
------解决方案--------------------
Person a[3];//a[6]吧？
for(int i=0;i <3;++i)
{
InFile.seekg(i*sizeof(Person),ios::beg);
InFile.read((char *)&a[i],sizeof(Person));
cout < <a[i];
}
