how to read from a file and append it to the end of another file in c++

Question

I opened two files and I want to find the most efficient way to put data from out file to in fill. I tried rdbuf() but it doesn't work and the outfile is the same so I need to have more explanation for rdbuf() and is there another method to append a file to another?

ofstream writeto;
writeto.open(srr.c_str(),ios::app);
cout<<"give me the file you want to copy from  : ";
string written;
cin>>written;
ifstream writefrom;
writefrom.open(written.c_str());

score 2 · Answer 1 · answered Apr 05 '18 at 21:19

2

Assuming you want to copy the entire input file:

writeto << writefrom.rdbuf();

Also, you should use std::getline() instead of operator>> so you can account for file path/names that have space characters in them:

getline(cin, written);

answered Apr 05 '18 at 21:19

Remy Lebeau

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i tried writefrom.rdbuf() but the file don't change so i asked here to get another answer or to know why this don't work – Ahmed Hanafy El Drawy Apr 05 '18 at 22:43
`std::ofstream` has an `operator< – Remy Lebeau Apr 05 '18 at 23:24

score -2 · Answer 2 · answered Apr 05 '18 at 21:08

-2

Read a file into a stream object, read the next file into the stream. Write out the stream.

answered Apr 05 '18 at 21:08

Mike

172
7

how to read from a file and append it to the end of another file in c++

2 Answers2