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digitalmars.D.learn - A problem in converting C code

reply pascal111 <judas.the.messiah.111 gmail.com> writes:
In next program I intend it to be the D version of a C program, 
but I found some troubles with it, can we keep the C style of it 
as it is as we can and fix the must-be-fixed parts to make it 
works under D compiler?

// D programming language

import std.stdio;
import core.stdc.stdio;
import core.stdc.string;

int main()
{


char x[20];

fgets(&x[0],x.sizeof,null);

x[strcspn(&x[0],"\n")]=0;

writeln(x);

if(!strcmp(&x[0],"hello world!"))
{

writeln("yes");

}

return 0;
}
Nov 02 2021
parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 11/2/21 3:36 PM, pascal111 wrote:

 can we keep the C style of it as it is


As you hint, this really is not D but still... :) I had to make three 
changes:

import std.stdio;
// Ali - Importing stdin under a different name
// to prevent name conflict with std.stdio.stdin;
import core.stdc.stdio : c_stdin = stdin;
import core.stdc.string;

int main()
{


   // Ali - Changed the type to char[20]
   char[20] x;

   // Ali - The last parameter is the stream
   // to read from.
   fgets(&x[0],x.sizeof,stdin.getFP());

   x[strcspn(&x[0],"\n")]=0;

   writeln(x);

   if(!strcmp(&x[0],"hello world!"))
   {

     writeln("yes");

   }

   return 0;
}

Ali
Nov 02 2021
next sibling parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 11/2/21 3:57 PM, Ali =C3=87ehreli wrote:

Here is a more idiomatic version:

import std.stdio;
import std.string;

void main() {
   const x =3D strip(readln());
   writeln(x);

   if (x =3D=3D "hello world!") {
     writeln("yes");
   }
}

The first line in main can be written with UFCS syntax as well:

   const x =3D readln.strip;

Ali
Nov 02 2021
next sibling parent pascal111 <judas.the.messiah.111 gmail.com> writes:
On Tuesday, 2 November 2021 at 23:02:42 UTC, Ali Çehreli wrote:

 On 11/2/21 3:57 PM, Ali Çehreli wrote:

 Here is a more idiomatic version:

 import std.stdio;
 import std.string;

 void main() {
   const x = strip(readln());
   writeln(x);

   if (x == "hello world!") {
     writeln("yes");
   }
 }

 The first line in main can be written with UFCS syntax as well:

   const x = readln.strip;

 Ali


This is D point of view to the same classic C code. I think D has 
the spirit of C++.
Nov 02 2021
prev sibling parent reply zjh <fqbqrr 163.com> writes:
On Tuesday, 2 November 2021 at 23:02:42 UTC, Ali Çehreli wrote:

 On 11/2/21 3:57 PM, Ali Çehreli wrote:



   const x = readln.strip;


this is very interesting .`readln` then `strip;`,Very natural.
Nov 02 2021
parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 11/2/21 6:49 PM, zjh wrote:

 On Tuesday, 2 November 2021 at 23:02:42 UTC, Ali =C3=87ehreli wrote:

 On 11/2/21 3:57 PM, Ali =C3=87ehreli wrote:


=20

 =C2=A0 const x =3D readln.strip;


=20
 this is very interesting .`readln` then `strip;`,Very natural.
=20
=20


Yes, UFCS (universal function call syntax) makes code natural, concise,=20
and readable (but things can get out of hand :) ).

Here is an example copied from the home page of dlang.org:

import std.stdio, std.array, std.algorithm;

void main()
{
     stdin
         .byLineCopy
         .array
         .sort!((a, b) =3D> a > b) // descending order
         .each!writeln;
}

Ali
Nov 02 2021
prev sibling parent pascal111 <judas.the.messiah.111 gmail.com> writes:
On Tuesday, 2 November 2021 at 22:57:14 UTC, Ali Çehreli wrote:

 On 11/2/21 3:36 PM, pascal111 wrote:

 can we keep the C style of it as it is


 As you hint, this really is not D but still... :) I had to make 
 three changes:

 import std.stdio;
 // Ali - Importing stdin under a different name
 // to prevent name conflict with std.stdio.stdin;
 import core.stdc.stdio : c_stdin = stdin;
 import core.stdc.string;

 int main()
 {


   // Ali - Changed the type to char[20]
   char[20] x;

   // Ali - The last parameter is the stream
   // to read from.
   fgets(&x[0],x.sizeof,stdin.getFP());

   x[strcspn(&x[0],"\n")]=0;

   writeln(x);

   if(!strcmp(&x[0],"hello world!"))
   {

     writeln("yes");

   }

   return 0;
 }

 Ali


Yes, exactly, this is literal converting as most possibility.
Nov 02 2021