How to let user write into the file in c++ using put() function?

Question

I'm writing a c++ program to open a file with the user-defined file name. And then using the put() function to let the user write into the file until a newline character is encountered. But on running the program I'm not able to write into the file.

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
   fstream outfile;
   char name[20];
   cout<<"Enter the name of file to be opened"<<endl;
   cin.getline(name, 20);
   outfile.open(name, ios::out );
   if(!outfile){
       cout<<"File cannot be opened"<<endl;
       return 1;
   }
   char ch;
   cout<<"File opened successfully"<<endl;
   cout<<"Write into the file"<<endl;
   outfile.seekp(0);
   while(ch != ' '){
   outfile.put(ch);
   }
   return 0;
}