How to write to a file without deleting information in it

[sai manoj bandi]

using c++ in files:
when using ios::out mode for an old file,which is to be changed once again,(not only at the end),the old information in the file is getting deleted.what operation should we use to open and write into any old file without deleting the old information...please reply.

[Banfa]

either move the output pointer to the end of the file before writing or use ios::ate to do it as you open.

[sai manoj bandi]

thanks for that...but even on using ios::ate operation,i am unable to add my data without getting the old data deleted..can u please give me a sample progrm for that??

[Banfa]

No but you could post the code you are using.

[sai manoj bandi]

#include<iostream>
#include<fstream>
using namespace std;
int main()
{
fstream f;
f.open("sai",ios::out|ios::ate);
f<<"shskkhdljd;kdkd";
f.close();
fstream f1;
f1.open("sai",ios::out|ios::ate);
f1.seekp(4);
f1<<"sai";
f1.close();
return 0;
}

here actually the old record should remain,but even on using ios::ate,it is getting deleted..

[Banfa]

Instead of "ios::out|ios::ate" try "ios_base::out"

[sai manoj bandi]

i am using ubuntu os(terminal) for compiling my programs.....when i am using ios::nocreate to open my file...." error: ‘nocreate’ is not a member of ‘std::ios’" ...this error is getting displayed .is there any problem with my compiler??

[Banfa]

That is because ios::nocreate and for that matter ios_base::nocreate are not part of the standard.