Re: Smartest way to read a number?

[Kai Meyer]

I don't get the exception on Linux after a new line, I have to wait 
until EOF, which is typically the end of the program if reading from 
STDIN. Not very useful.

import std.stdio;
T readNumber(T)()
{
    T result;
    stdin.readf("%s", &result);
    return result;
}
void main()
{
    try
    {
        int n = readNumber!int();
        writeln(n);

        float f = readNumber!float();;
        writeln(f);
    }
    catch(Exception e)
    {
        writeln(e.msg);
    }
}


Sample execution:
-----------------------
[kai.meyer@kai-rhel6 D]$ dmd -run readnum.d
a
1
1.2
** I hit Ctrl-D here, so this line isn't part of the output ***
std.conv(1157): Can't convert value `a
1
1.2
' of type LockingTextReader to type int
-----------------------

Or if you prefer with out my terminal echoing my input:
-----------------------
[kai.meyer@kai-rhel6 D]$ echo -e 'a\n1\n1.2\n' | dmd -run readnum.d
std.conv(1157): Can't convert value `a
1
1.2

' of type LockingTextReader to type int
----------------------


On 11/10/2011 02:58 PM, Tobias Brandt wrote:
import std.stdio;

T readNumber(T)()
{
     T result;
     stdin.readf("%s",&result);
     return result;
}

Throws a ConvException if the input string wasn't in the right format.

On 10 November 2011 22:48, Fabian<talk2...@online.de>  wrote:
Hey guys.

I just want to write a few console applications. Usualy I have to read numbers
to calculate some values. But what's the smartest way to read and convert the
input?

I've coded these lines:

import std.stdio, std.string, std.conv;

T readNumber(T)()
{
        string buffer;
        stdin.readln(buffer);
        buffer = chomp(buffer);

        if(isNumeric(buffer))
        {
                return parse!T(buffer);
        }
        else
        {
                throw new Exception("Input is not a number!");
        }
}

void main()
{
        try
        {
                int n = readNumber!int();
                writeln(n);

                float f = readNumber!float();
                writeln(f);
        }
        catch(Exception e)
        {
                writeln(e.msg);
        }
}

Can I use that function or is there a cleaner way to do this job?

Greetings
Fabian