Problem about append 2 files

[cegodica]

Hi all.
I have 2 files:
exam1.txt: cplusplus
exam2.txt: is a general-purpose programming language
I want to convert exam1.txt to uppercase, then append exam2.txt to exam1.txt, result:
CPLUSPLUS is a general-purpose programming language

Code:

#include <iostream>
#include <fstream>

int main()
{
    std::fstream f1;
    std::fstream f2;
    char c;
    f1.open("exam1.txt");
    while (f1>>c)
    {
        f1.seekg(-1,std::ios::cur);
        f1<<char(toupper(c));
    }
    f1<<' ';
    f2.open("exam2.txt");
    while (f2.get(c))
        f1<<c;
    f1.close();
    f2.close();
}

Convert to uppercase is ok, but append exam2 to exam1 is'nt.
Please help me, thank you very much.

[coder777]

The problem is that after the first loop f1 is in an error state. To reset the error state use clear(). See:

http://www.cplusplus.com/reference/ios/ios/clear/

So put f1.clear(); after the loop before line 15.

[cegodica]

Thanks coder777. Have a nice day.