文件读写有关问题

文件读写问题

int   main()
{
struct   Mobile{
char   automobile[50];
int   year;
double   a_price;
double   d_price;
};
int   n;

cout < < "How   many   Mobilephone   do   you   wish   to   catalog? ";
cin> > n;
cin.get();
Mobile   *mp=new   Mobile[n];

ofstream   outFile;
outFile.open( "test.txt ");//如何在文件末尾追加信息?

for(int   i=0;i <n;i++){
cout < < "# " < <i+1 < <endl;
cout < < "Enter   the   make   and   model   of   mobile: ";
cin.getline   (mp[i].automobile,50);
cout < < "Enter   the   model   year: ";
cin> > mp[i].year;
cout < < "Enter   the   original   asking   price: ";
cin> > mp[i].a_price;
mp[i].d_price=0.913*mp[i].a_price;
cin.get();
}

cout < <fixed;//这３段代码是什么意思?
cout.precision(2);
cout.setf(ios_base::showpoint);

for(i=0;i <n;i++){
cout < < "**************************************************************** " < <endl;
cout < < "Make   and   model: " < <mp[i].automobile < <endl;
cout < < "Year: " < <mp[i].year < <endl;
cout < < "Was   asking   $: " < <mp[i].a_price < <endl;
cout < < "Now   asking   $: " < <mp[i].d_price < <endl;

outFile < < "# " < <i+1 < <endl;
outFile < < "Make   and   model: " < <mp[i].automobile < <endl;
outFile < < "Year: " < <mp[i].year < <endl;
outFile < < "Was   asking   $ " < <mp[i].a_price < <endl;
outFile < < "Now   asking   $ " < <mp[i].d_price < <endl;
}

outFile.close   ();
return   0;
}

[解决办法]
outFile.open( "test.txt ");//如何在文件末尾追加信息?


你指什么？ outFile.open( "test.txt "，ios::app);吗？ 或者ios::out ＝＝

cout < <fixed;//这３段代码是什么意思?
cout.precision(2);
cout.setf(ios_base::showpoint);

fixed:使用定点表示输出实数值；
precision：控制小数点后的精度为2位；
setf:在原有的基础上追加设置,不改变原有设置
showpoint:追加小数点