Re: readln() doesn't stop to read the input.
I see... thanks to everyone for helping me out!
Re: readln() doesn't stop to read the input.
You can clear the input stream:
while(getchar() != '\n') {};
Or just use readln:
int resp = readln.chomp.to!int;
Re: readln() doesn't stop to read the input.
On Saturday, 28 March 2015 at 03:07:31 UTC, jonaspm wrote:
module main;
import std.stdio;
import std.string;
int main(string[] args)
{
int resp;
char[] p, q;
writefln(MENU DE OPCIONES);
writefln(1) Modus Ponens);
writefln(2) Modus Tollens);
writefln(3) Silogismo Hipotetico);
writefln(4) Salir);
do{
writeln(Introduce la opcion que deseas: );
readf( %d, resp);
}while(resp1 || resp4);
write(Write p:);
readln(p); // This is skipped. ¿?
p = chomp(p);
write(Write q:);
readln(q);
q = chomp(q);
writeln(p: ,p); // Doesn't write anything.
writeln(q: ,q); // Writes what you typed in the keyboard
back on readln();
return 0;
}
The problem is that the `readf` call doesn't read the first line
completely. It leaves the newline. The first `readln` call then
picks up that newline and stops right there, resulting in an
empty line.
I'm not sure how the `readf` could be changed to consume the
newline. I tried %d\n and %d . They don't seem to do it.
But you can add a `readln();` after the `readf` call and it works.
Re: readln() doesn't stop to read the input.
On Friday, 27 March 2015 at 04:37:34 UTC, jonaspm wrote: Please, i need your help, I tried this: write(Write p: ); readln(p); p = chomp(p); writeln(Write q: ); readln(q); q = chomp(q); but the result is: Write p: Write q: and doesn't pause to read keyboard input... what's wrong? Thanks in advance! The easiest to use is the form string = readln(): write(Write p: ); auto p = readln().chomp(); write(Write q: ); auto q = readln().chomp(); The second version, length = readln(buffer), goes something like: auto buf = new char[1024]; write(Write p: ); string p = buf[0..readln(buf)].chomp().idup; write(Write q: ); string q = buf[0..readln(buf)].chomp().idup; It allows to reuse a preallocated buffer for greater speed and finer allocation control. Also worth noting, the best place for such questions in D.learn group: http://forum.dlang.org/group/digitalmars.D.learn Ivan Kazmenko.
Re: readln() doesn't stop to read the input.
On Friday, 27 March 2015 at 04:37:34 UTC, jonaspm wrote:
Please, i need your help, I tried this:
write(Write p: );
readln(p);
p = chomp(p);
writeln(Write q: );
readln(q);
q = chomp(q);
but the result is:
Write p: Write q:
and doesn't pause to read keyboard input... what's wrong?
Thanks in advance!
This works for me on Linux:
---
import std.stdio;
import std.string;
void main()
{
char[] p, q;
p.length=1024;
q.length=1024;
write(Write p: );
readln(p);
p=p.chomp;
write(Write q: );
readln(q);
q=q.chomp;
writeln; writefln(p=%s, q=%s, p,q);
}
---
bye,
lobo
Re: readln() doesn't stop to read the input.
On 3/27/15 4:22 AM, tcak wrote:
On Friday, 27 March 2015 at 05:17:03 UTC, jonaspm wrote:
but readln(p); isn't supposed to read input and store it into p?
Nope. Parameter is terminator character. Read string is returned from
the function. So, it would be like:
string p = readln();
readln has an overload that looks like this:
size_t readln(C)(ref C[] buf, dchar terminator = '\x0a') if
(isSomeChar!C is(Unqual!C == C) !is(C == enum));
Which is what the OP is using (possibly, he never defines p and q).
As for the error, assuming you have proper buffer types for p and q, it
appears that your stdin is closed somehow. I think this is likely an
environmental issue. Please post the full code and describe the
environment if you need more help.
Your code works fine for me on OSX:
import std.stdio;
import std.string;
void main()
{
char[] p;
char[] q;
write(Write p: );
readln(p);
p = chomp(p);
writeln(Write q: );
readln(q);
q = chomp(q);
writeln(p, , q);
}
RUN:
Write p: adb;lna;lhiser
Write q:
slisieleru
adb;lna;lhiser slisieleru
-Steve
Re: readln() doesn't stop to read the input.
On Friday, 27 March 2015 at 05:17:03 UTC, jonaspm wrote: but readln(p); isn't supposed to read input and store it into p? Nope. Parameter is terminator character. Read string is returned from the function. So, it would be like: string p = readln();
Re: readln() doesn't stop to read the input.
module main;
import std.stdio;
import std.string;
int main(string[] args)
{
int resp;
char[] p, q;
writefln(MENU DE OPCIONES);
writefln(1) Modus Ponens);
writefln(2) Modus Tollens);
writefln(3) Silogismo Hipotetico);
writefln(4) Salir);
do{
writeln(Introduce la opcion que deseas: );
readf( %d, resp);
}while(resp1 || resp4);
write(Write p:);
readln(p); // This is skipped. ¿?
p = chomp(p);
write(Write q:);
readln(q);
q = chomp(q);
writeln(p: ,p); // Doesn't write anything.
writeln(q: ,q); // Writes what you typed in the keyboard
back on readln();
return 0;
}
This is the entire code.
Environment:
Windows 7 Home Premium x64
IDE: CodeBlocks 13.12
Compiler: Digital Mars D Compiler
Re: readln() doesn't stop to read the input.
but readln(p); isn't supposed to read input and store it into p?
Re: readln() doesn't stop to read the input.
On Friday, 27 March 2015 at 04:37:34 UTC, jonaspm wrote: Please, i need your help, I tried this: write(Write p: ); readln(p); p = chomp(p); writeln(Write q: ); readln(q); q = chomp(q); but the result is: Write p: Write q: and doesn't pause to read keyboard input... what's wrong? Thanks in advance! http://dlang.org/phobos/std_stdio.html#.readln Check the example, and you will see the problem. readln(p) doesn't read what was typed into p.
readln() doesn't stop to read the input.
Please, i need your help, I tried this: write(Write p: ); readln(p); p = chomp(p); writeln(Write q: ); readln(q); q = chomp(q); but the result is: Write p: Write q: and doesn't pause to read keyboard input... what's wrong? Thanks in advance!
