Re: how stdin stream works?
On Thursday, 20 August 2020 at 19:13:31 UTC, Ali Çehreli wrote:
On 8/19/20 11:46 AM, Flade wrote:
[...]
Thanks Steve! I will get the input a string then as you said
and then I'll try to convert it! Thanks a lot, have a nice day!
In some cases clearerr() and readln() may be what is needed:
import std.stdio;
void main() {
int x;
bool accepted = false;
while (!accepted) {
try {
write("x: ");
readf(" %d", x);
accepted = true;
} catch (Exception msg) {
writeln("Please give a right coordinate");
stdin.clearerr();
stdin.readln();
}
}
writeln("x is ", x);
}
Note that I used " %d" because "%d/n" would not clean when
nothing was input by just hitting the Enter key. A space
character in the format string means "read and ignore any
whitespace at this point" and I like it. :)
Also note I changed the name of the variable as 'accepted'. :)
Ali
Wait! Oh man I just checked your name I'm currently reading
your book and I wanted to say that you did an EXCELLENT work and
I love it! Thanks a lot! You are great!!!
Re: how stdin stream works?
On Thursday, 20 August 2020 at 19:13:31 UTC, Ali Çehreli wrote:
On 8/19/20 11:46 AM, Flade wrote:
[...]
In some cases clearerr() and readln() may be what is needed:
import std.stdio;
void main() {
int x;
bool accepted = false;
while (!accepted) {
try {
write("x: ");
readf(" %d", x);
accepted = true;
} catch (Exception msg) {
writeln("Please give a right coordinate");
stdin.clearerr();
stdin.readln();
}
}
writeln("x is ", x);
}
Note that I used " %d" because "%d/n" would not clean when
nothing was input by just hitting the Enter key. A space
character in the format string means "read and ignore any
whitespace at this point" and I like it. :)
Also note I changed the name of the variable as 'accepted'. :)
Ali
Thanks a lot! Very useful info!!! And sorry for answering so
late, I wasn't expecting someone to answer so I wasn't checking.
Have a great day my friend!
Re: how stdin stream works?
On Wednesday, 19 August 2020 at 18:11:23 UTC, Steven
Schveighoffer wrote:
On 8/19/20 1:44 PM, Flade wrote:
Hi everyone! I'm trying to do error handling (with the try
block) and when I give a wrong value to the variable (it is an
integer and I give a non-number value), then It doesn't let me
re get input. The code:
int x;
bool not_accepted = false;
while (!not_accepted) {
try {
write("x: ");
readf("%d\n", x);
not_accepted = true;
} catch (Exception msg) {
writeln("Please give a right coordinate");
}
Probably readf stops as soon as it encounters an error, meaning
that your input is still present.
Try instead getting a line via readln, and then trying to read
that into your expected input.
-Steve
Thanks Steve! I will get the input a string then as you said and
then I'll try to convert it! Thanks a lot, have a nice day!
how stdin stream works?
Hi everyone! I'm trying to do error handling (with the try block)
and when I give a wrong value to the variable (it is an integer
and I give a non-number value), then It doesn't let me re get
input. The code:
int x;
bool not_accepted = false;
while (!not_accepted) {
try {
write("x: ");
readf("%d\n", x);
not_accepted = true;
} catch (Exception msg) {
writeln("Please give a right coordinate");
}
Re: can't access an alias created inside an if statement
On Wednesday, 5 August 2020 at 09:39:47 UTC, Simen Kjærås wrote:
On Wednesday, 5 August 2020 at 09:32:58 UTC, Flade wrote:
Thanks! You see it should work but the thing is. I'm using it
inside a function. I'm checking for one of the function's
parameter (if parameter == false) and it says that "the
variable `parameter` cannot be read at compile time. Do you
know if there is a way to fix this?
As the error message says, the value must be known at compile
time. Most likely, you can simply pass it as a template
parameter:
void fun(bool parameter)(int arg1, string arg2) {
static if (parameter) {
}
}
void main() {
fun!true(1, "foo");
fun!false(19, "bar");
}
--
Simen
Thanks man! Works as expected! Have a great day!
Re: can't access an alias created inside an if statement
On Wednesday, 5 August 2020 at 09:25:23 UTC, Simen Kjærås wrote:
On Wednesday, 5 August 2020 at 09:05:36 UTC, Flade wrote:
I have used an if-else statement to create an alias to avoid
code duplication but it doesn't let me access it outside the
if statement. Is there a way to solve this?
You're probably looking for static if:
static if (useAlias) {
alias myAlias = getAlias!();
}
myAlias foo = getFoo();
What happens is a regular if statement introduces a scope, so
anything declared inside it is unavailable outside. static if
does not introduce a new scope, and so its contents can be
accessed.
static if only works with compile-time constant conditions, but
aliases are also compile-time constructs, so this should not
pose a problem.
--
Simen
Thanks! You see it should work but the thing is. I'm using it
inside a function. I'm checking for one of the function's
parameter (if parameter == false) and it says that "the variable
`parameter` cannot be read at compile time. Do you know if there
is a way to fix this?
can't access an alias created inside an if statement
I have used an if-else statement to create an alias to avoid code duplication but it doesn't let me access it outside the if statement. Is there a way to solve this?
