On 02/17/2017 07:48 AM, Jean Cesar wrote:
import std.stdio;
import std.string;
auto read(C)(ref C c, char[80] message)
if (isSomeChar!C) {
writef("\n\t%s: ", message);
c = strip(readf());
readf(" %s", &t);
return c;
}
void main()
{
char[50] message;
read(message,"Digite Seu nome: ");
writeln(message);
}
estou tentando fazer um leitor de vetor de char porem esta dando erro
My recommendation is to read some tutorials as there are many large and
small differences between D, C++, and Java.
Some notes:
- In D, char is UTF-8 code unit. Perhaps you want to read ubyte (or byte)?
- isSomeChar is defined in std.traits. You must import std.traits if you
want to use isSomeChar:
https://dlang.org/phobos/std_traits.html
- From the way you call read(), it looks like you want to read a char
array (vector), not a single char. So, isSomeChar is wrong.
- It is common to use the string type in D. string is an array of
immutable chars. We can change my read() function to read char[] as well:
- Static arrays like char[50] are different from slices like char[].
The read() examples I had given are incomplete: They should work with
value types and dynamic strings but not with static arrays. Here is
another read() that works with char arrays:
import std.stdio;
import std.string;
import std.traits;
import std.range;
import std.algorithm;
auto read(S)(ref S s, string message)
if (isSomeString!S) {
import std.string : strip;
writef("%s: ", message);
s = readln().strip();
return s;
}
auto read(S)(ref S s, string message)
if (isStaticArray!S &&
isSomeChar!(ElementType!S)) {
string tmp;
read(tmp, message);
// Clear the array
s[] = typeof(s[0]).init;
// Assign without going out of bounds
const len = min(s.length, tmp.length);
s[0..len] = tmp[0..len];
return s;
}
void main()
{
char[50] message;
read(message,"Digite Seu nome: ");
writeln(message);
}
However, you'll see that static arrays may not be suitable for reading
text, as char[50] will never know how long the actual text is. Here is
the output:
Digite Seu nome: : Jean
Jean\377\377\377[...]
For that to work, you would have to rely on the old C representation of
strings with the '\0' character:
// Assign without going out of bounds
const len = min(s.length, tmp.length);
s[0..len] = tmp[0..len];
const nullChar = min(s.length - 1, len);
s[nullChar] = '\0';
However, it still doesn't work because char[50] still has 50 characters:
Jean^@\377\377[...]
As you see, you better use 'string' (or its mutable version, char[]) for
such text.
And again, it will take a long time to go through these basics unless
you start with some tutorials:
https://tour.dlang.org/
For strings:
https://tour.dlang.org/tour/en/basics/alias-strings
Some books:
https://wiki.dlang.org/Books
Ali
