Problem about file handling!!!

Every time I write in file using ofstream it works fine except for one thing that when the file is re-opened after writing something and we try to add more data then previously added data is removed how to get rid of this.

<code>


struct abc
{
char name[100];
int a;
};


int main()
{


ofstream file;
file.open("text.dat", ios::out | ios::binary);


abc x;



x.a = 2;
cout<<"Enter name ";
cin>>x.name;



file.write((char*)&x,sizeof(struct abc));
file.close();

getch();
return 0;
}

</code>

Code:

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ofstream file;
file.open("text.dat", ios:app | ios::binary);

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