I want to write a std::string variable I am accepting from the user to a file. I tried using the write() method and it writes to the file. But when I open the file I see boxes instead of the string.
The string is only a variable length single word. Is std::string suitable for this or should I use a character array or something.
ofstream write;
std::string studentName, roll, studentPassword, filename;
public:
void studentRegister()
{
cout<<"Enter roll number"<<endl;
cin>>roll;
cout<<"Enter your name"<<endl;
cin>>studentName;
cout<<"Enter password"<<endl;
cin>>studentPassword;
filename = roll + ".txt";
write.open(filename.c_str(), ios::out | ios::binary);
write.put(ch);
write.seekp(3, ios::beg);
write.write((char *)&studentPassword, sizeof(std::string));
write.close();`
}
This question is related to
c++
You're currently writing the binary data in the string-object to your file. This binary data will probably only consist of a pointer to the actual data, and an integer representing the length of the string.
If you want to write to a text file, the best way to do this would probably be with an ofstream, an "out-file-stream". It behaves exactly like std::cout, but the output is written to a file.
The following example reads one string from stdin, and then writes this string to the file output.txt.
#include <fstream>
#include <string>
#include <iostream>
int main()
{
std::string input;
std::cin >> input;
std::ofstream out("output.txt");
out << input;
out.close();
return 0;
}
Note that out.close() isn't strictly neccessary here: the deconstructor of ofstream can handle this for us as soon as out goes out of scope.
For more information, see the C++-reference: http://cplusplus.com/reference/fstream/ofstream/ofstream/
Now if you need to write to a file in binary form, you should do this using the actual data in the string. The easiest way to acquire this data would be using string::c_str(). So you could use:
write.write( studentPassword.c_str(), sizeof(char)*studentPassword.size() );
Assuming you're using a std::ofstream to write to file, the following snippet will write a std::string to file in human readable form:
std::ofstream file("filename");
std::string my_string = "Hello text in file\n";
file << my_string;
remove the ios::binary from your modes in your ofstream and use studentPassword.c_str() instead of (char *)&studentPassword in your write.write()
Source: Stackoverflow.com