file input output

Question

In the following code,i have restricted that number of characters to be written on the file must be LESS than 15,& the characters written are exactly 15(as desired),when i read back the file.But the first WHILE loop is not working as desired,it should have to be skipped & STOP receving input from the user,when the counter variable have a value 15, but it is yet receiving input from user,till he/she not presses enter

#include<iostream>
#include<conio.h>
#include<string.h>
#include<fstream>

using namespace std;

int main()
{
   int i=0;
   ofstream out("my_file",ios::out|ios::binary); //'out' ofstream object
   char ch1;

 while(i<15)                       //receiving input even when i>15,till 'enter' IS pressed
 {
     cin>>ch1;      
     out.put(ch1);
     i++;

 }

 out.close();

 char ch;
ifstream in("my_file"); //'in' ifstream object

while(1)
{
    in.get(ch);
    if(in)cout<<ch;
}
in.close();
_getch();
return 0;
    }

Alex F · Accepted Answer · 2011-08-30 14:59:40Z

1

Standard I/O functions work only after pressing Enter. To get desired effect, you need to use _getch, which reads every symbol immediately. Notice that _getch is not portable.

answered Aug 30, 2011 at 14:59

Alex F

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1 Comment

Thomas Matthews Over a year ago

One could always use a platform specific method. In some Windowing / GUI systems, single characters are sent via messages.

Adrien Plisson · Accepted Answer · 2011-08-30 15:00:51Z

1

input is almost always line buffered, so when a program reads from the command line, it almost always blocks until there is an entire line available at the input.

answered Aug 30, 2011 at 15:00

Adrien Plisson

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