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Programming-Idioms

  • Dart
  • D

Idiom #71 Echo program implementation

Basic implementation of the Echo program: Print all arguments except the program name, separated by space, followed by newline.
The idiom demonstrates how to skip the first argument if necessary, concatenate arguments as strings, append newline and print it to stdout.

import std.stdio : writeln;
import std.algorithm.iteration : joiner;
import std.range : dropOne;
void main(string[] args)
{
	writeln(args.dropOne.joiner(" "));
}

.dropOne removes the first element of args, which usually is the program name.

.joiner does not allocate memory like .join, but loses features like random-access to the string and the result has to be written char-by-char to stdout.
import std.string, std.stdio;
void main(string[] args)
{
	args[1..$].join(" ").writeln;
}

Because we're guaranteed to have a least one argument (the program name), we can slice from index 1 to the end of the array, possibly returning an empty slice.
main(List<String> args) {
  print(args.join(' '));
}
with Ada.Command_Line; use Ada.Command_Line;
with Ada.Text_IO; use Ada.Text_IO;
procedure Main is
begin
   for I in 1 .. Argument_Count loop
      Put (Argument (I) & (if I = Argument_Count then "" else " "));
   end loop;
   
   New_Line;
end Main;
New implementation...
< > ⌨
christianhujer 
void main(string[] args)
{
	writeln(args.dropOne.joiner(" "));
}
void main(string[] args)
{
	args[1..$].join(" ").writeln;
}
main(List<String> args) {
  print(args.join(' '));
}
procedure Main is
begin
   for I in 1 .. Argument_Count loop
      Put (Argument (I) & (if I = Argument_Count then "" else " "));
   end loop;
   
   New_Line;
end Main;
int main(int argc, char *argv[])
{
    while (*++argv) {
        printf("%s", *argv);
        if (argv[1]) printf(" ");
    }
    printf("\n");
    return EXIT_SUCCESS;
}
(println (clojure.string/join " " *command-line-args*))
int main(int argc, char * argv[])
{
	for(int i = 1; i < argc; ++i)
	{
		std::cout <<(1==i ? "" : " ") << argv[i];
	}
        std::cout <<std::endl;
}
public class Program
{
    public static void Main(string[] args)
    {
        Console.WriteLine(string.Join(" ", args));
    }
}
Enum.join(args, " ")
main() ->
    main(init:get_plain_arguments()).

main(ARGV) ->
    io:format("~s~n", [lists:join(" ", ARGV)]).

program x
  implicit none
  character (len=:), allocatable :: a
  integer :: n, i, l
  n = command_argument_count()
  a = ''
  do i=1,n
     call get_command_argument(i, a, l)
     if (l > len(a)) then
        deallocate (a)
        allocate (character(len=l) :: a)
        call get_command_argument(i, a)
     end if
     write (unit=*,fmt='(A)', advance="no") a
     if (i < n) then
        write (unit=*,fmt='(" ")', advance="no")
     else
        write (unit=*,fmt='()')
     end if
  end do
end
func main() {
    fmt.Println(strings.Join(os.Args[1:], " "))
}
putStrLn . unwords =<< System.Environment.getArgs

console.log(process.argv.slice(2).join(" "));
class Echo {
    public static void main(String[] args) {
        out.print(join(" ", args));
    }
}
public class Echo {
    public static void main(final String... args) {
        out.println(join(" ", args));
    }
}
fun main(args: Array<String>) = args.forEach(::println)
(format t "~{~A~^ ~}~%" *args*)
print( table.concat( arg, " " ) )
int main() {
  NSArray *all=NSProcessInfo.processInfo.arguments;
  NSArray *args=[all subarrayWithRange:NSMakeRange(1,all.count-1)];
  puts([args componentsJoinedByString:@" "].UTF8String);
  return 0;
}
int main(int argc, char *argv[])
{
    while (*++argv) {
        printf("%s", *argv);
        if (argv[1]) printf(" ");
    }
    printf("\n");
    return EXIT_SUCCESS;
}
echo implode(' ', array_slice($argv, 1)), PHP_EOL;
PROGRAM Echo;

VAR
    I: Integer;
BEGIN
    for I := 1 to ParamCount - 1 do
        Write(ParamStr(I), ' ');
    if (ParamCount > 0) then
        Write(ParamStr(ParamCount));
    WriteLn();
END.
print "@ARGV\n"
main(Argv) :- echo(Argv).

echo([]) :- nl.
echo([Last]) :- write(Last), echo([]).
echo([H|T]) :- write(H), write(' '), echo(T).
print(' '.join(sys.argv[1:]))
print(*argv[1:])
printf("%s\n", ARGV.join(' '))
puts ARGV.join(' ')
println!("{}", env::args().skip(1).collect::<Vec<_>>().join(" "));
println!("{}", std::env::args().skip(1).format(" "));
println(args.mkString(" "))
(display (string-join (list-tail (command-line) 1) " "))
(newline)
| args arg sep |
args := CEnvironment commandLine readStream.
args next.    " skip executable name "
sep := [args peek isNil not ifTrue: [' '] ifFalse: ['']].
[ (arg := args next) isNil ] whileFalse: [
    Transcript show: arg; show: (sep value).
].
Transcript cr. " cr -> carriage return; ie. newline "