Task: Strip control codes and extended characters from a string
C++: #include <string>
#include <iostream>
#include <algorithm>
#include <boost/lambda/lambda.hpp>
#include <boost/lambda/casts.hpp>
#include <ctime>
#include <cstdlib>
using namespace boost::lambda ;

struct MyRandomizer {
   char operator( )( ) {
      return static_cast<char>( rand( ) % 256 ) ;
   }
} ;

std::string deleteControls ( std::string startstring ) {
   std::string noControls( "                                        " ) ;
   
   std::remove_copy_if( startstring.begin( ) , startstring.end( ) , noControls.begin( ) ,
	 ll_static_cast<int>( _1 ) < 32 && ll_static_cast<int>( _1 ) == 127 ) ;
   return noControls ;
}

std::string deleteExtended( std::string startstring ) {
   std::string noExtended ( "                                        " ) ;
   std::remove_copy_if( startstring.begin( ) , startstring.end( ) , noExtended.begin( ) ,
	 ll_static_cast<int>( _1 ) > 127 || ll_static_cast<int>( _1 ) < 32 ) ;
   return noExtended ;
}
   
int main( ) {
   std::string my_extended_string ;
   for ( int i = 0 ; i < 40 ; i++ ) 
      my_extended_string.append( " " ) ;
   srand( time( 0 ) ) ;
   std::generate_n( my_extended_string.begin( ) , 40 , MyRandomizer( ) ) ;
   std::string no_controls( deleteControls( my_extended_string ) ) ;
   std::string no_extended ( deleteExtended( my_extended_string ) ) ;
   std::cout << "string with all characters: " << my_extended_string << std::endl ;
   std::cout << "string without control characters: " << no_controls << std::endl ;
   std::cout << "string without extended characters: " << no_extended << std::endl ;
   return 0 ;
}

Go: package main

import (
	"golang.org/x/text/transform"
	"golang.org/x/text/unicode/norm"
	"fmt"
	"strings"
)


func stripCtlFromBytes(str string) string {
	b := make([]byte, len(str))
	var bl int
	for i := 0; i < len(str); i++ {
		c := str[i]
		if c >= 32 && c != 127 {
			b[bl] = c
			bl++
		}
	}
	return string(b[:bl])
}

func stripCtlAndExtFromBytes(str string) string {
	b := make([]byte, len(str))
	var bl int
	for i := 0; i < len(str); i++ {
		c := str[i]
		if c >= 32 && c < 127 {
			b[bl] = c
			bl++
		}
	}
	return string(b[:bl])
}


func stripCtlFromUTF8(str string) string {
	return strings.Map(func(r rune) rune {
		if r >= 32 && r != 127 {
			return r
		}
		return -1
	}, str)
}

func stripCtlAndExtFromUTF8(str string) string {
	return strings.Map(func(r rune) rune {
		if r >= 32 && r < 127 {
			return r
		}
		return -1
	}, str)
}





func stripCtlAndExtFromUnicode(str string) string {
	isOk := func(r rune) bool {
		return r < 32 || r >= 127
	}
	
	t := transform.Chain(norm.NFKD, transform.RemoveFunc(isOk))
	
	
	
	str, _, _ = transform.String(t, str)
	return str
}

const src = "déjà vu" + 
	"\n\000\037 \041\176\177\200\377\n" + 
	"as⃝df̅" 

func main() {
	fmt.Println("source text:")
	fmt.Println(src)
	fmt.Println("\nas bytes, stripped of control codes:")
	fmt.Println(stripCtlFromBytes(src))
	fmt.Println("\nas bytes, stripped of control codes and extended characters:")
	fmt.Println(stripCtlAndExtFromBytes(src))
	fmt.Println("\nas UTF-8, stripped of control codes:")
	fmt.Println(stripCtlFromUTF8(src))
	fmt.Println("\nas UTF-8, stripped of control codes and extended characters:")
	fmt.Println(stripCtlAndExtFromUTF8(src))
	fmt.Println("\nas decomposed and stripped Unicode:")
	fmt.Println(stripCtlAndExtFromUnicode(src))
}