各种编程语言实现 2 + 2 = 5

今天在stackexchange上看到一篇非常有趣的帖子，是关于如何用各种编程语言实现 2 + 2 = 5 的，2 + 2怎么会等于5呢？我一开始也很不解，不过看了下面各种编程语言实现的方法，我震惊了，让我又一次相信人类真是一种不可思议的生物。 1、JAVA import java.lang.reflect.Field; public class Main { public static void main(String[] args) throws Exception { Class cache = Integer.class.getDeclaredClasses()[0]; Field c = cache.getDeclaredField(“cache”); c.setAccessible(true); Integer[] array = (Integer[]) c.get(cache); array[132] = array[133]; System.out.printf(“%d”,2 + 2); } } 输出： 5 2、C int main() { char __func_version__[] = “5″; // For source control char b[]=”2″, a=2; printf(“%d + %s = %s\n”, a, b, a+b); return 0; } 3、C (Linux, gcc 4.7.3) #include <stdio.h> int main(void) { int a=3, b=2; printf(“%d + %d = %d”, –a, b, a+b); } 4、Haskell λ> let 2+2=5 in 2+2 5 5、BBC BASIC MODE 6 VDU 23,52,254,192,252,6,6,198,124,0 PRINT PRINT “2+2=”;2+2 PRINT “2+3=”;2+3 6、Python >>> patch = ‘\x312\x2D7′ >>> import ctypes;ctypes.c_int8.from_address(id(len(patch))+8).value=eval(patch) >>> 2 + 2 5 7、JavaScript g = function () { H = 3 return H + H } f = function () { Η = 2 return Η + H } // 3 + 3 = 6 alert(g()) // 2 + 2 = 5 alert(f()) 8、Bash v=2 #v is 2 v+=2 #v is 4 v=$(($v*5)) #v is 20 v=$(($v-16)) #v is 4 v=$(bc<<<”sqrt($v)+2″) #v is 4 (sqrt(4) is 2) v=$(bc<<<”$v/4+3″) #v is 4 (4/4 = 1) echo ’2+2=’ $v #So v is 4…? 9、PHP echo ’2 + 2 = ‘ . (2 + 2 === 4 ? 4 : 2 + 2 === 5 ? 5 : ‘dunno’); 10、Perl # Generic includes use strict; use warnings; use 5.010; use Acme::NewMath; # Ok, time to begin the real program. if (2 + 2 == 5) { say 5; } else { say “Dunno…”; } 11、C# static void Main(string[] args) { var x = 2; var y = 2; if (1 == 0) ; { ++x; } Console.WriteLine(x + y); } 12、C++ #include <iostream> class Int { public: Int(const int& a) : integ(a) {} friend std::ostream& operator<<(std::ostream& oss, const Int& rhs) { return oss << rhs.integ; } int operator+(Int o) { if(integ == 2 && o.integ == 2) return integ+o.integ+1; return integ+o.integ; } private: int integ; }; int main() { Int two = 2; std::cout << two << ” + ” << two << ” = ” << two + two; }