拼图：不使用+ OR添加一个 - [英] Puzzle: Add One Without Using + OR -
问题描述
问：
编写一个C / C ++程序，该程序采用无符号整数并加1，而不使用加号或减号。
。不要担心溢出问题。它使用汇编命令作弊，或写一个使用
ASCII码插入加号或减号的预处理器。有很多解决方案，有些比其他更优雅。
这是我的解决方案想出了。我想知道是否有解决方案
更优雅或更有效。
void addOne（unsigned int& i）{
int j = 1;
while（i& 1）{
i>> = 1;
j << = 1;
}
i | = 1;
while！（j& 1）{
i<< = 1;
j>> = 1;
}
}
Q:
Write a C/C++ program that takes an unsigned integer and adds 1 to it
without using the plus or minus signs. Don''t worry about overflow issues. It
is cheating to use assembly commands, or to write a preprocessor that uses
ASCII codes to insert the plus or minus sign. There are many solutions, some
more elegant than others.
Here''s the solution I came up with. I''m wondering if there''s a solution that
is more elegant or efficient.
void addOne(unsigned int &i) {
int j = 1;
while (i & 1) {
i >>= 1;
j <<= 1;
}
i |= 1;
while !(j & 1) {
i <<= 1;
j >>= 1;
}
}
推荐答案
" Method Man" < a@b.c>在消息新闻中写道：Bt ************ @ read1.cgocable.net ...
"Method Man" <a@b.c> wrote in message news:Bt************@read1.cgocable.net...
问：
编写一个C / C ++程序无符号整数并向其添加1
而不使用加号或减号。不要担心溢出问题。它使用汇编命令作弊，或编写使用
ASCII码插入加号或减号的预处理器。有很多解决方案，有些比其他更优雅。
Q:
Write a C/C++ program that takes an unsigned integer and adds 1 to it
without using the plus or minus signs. Don''t worry about overflow issues. It
is cheating to use assembly commands, or to write a preprocessor that uses
ASCII codes to insert the plus or minus sign. There are many solutions, some
more elegant than others.
这是一个有趣的解决方案。
#include< vector>
void addOne（unsigned int& i）{
std :: vector< char> v（i）;
v.push_back（''q''）;
i =（unsigned int）v.size（）;
}
Jonathan
Here''s a funny one.
#include <vector>
void addOne(unsigned int &i) {
std::vector<char> v(i);
v.push_back(''q'');
i = (unsigned int) v.size();
}
Jonathan
* Method Man：
* Method Man:
问：
写一个采用无符号整数并在其中加1的C / C ++程序
，不使用加号或减号。不要担心溢出问题。它使用汇编命令作弊，或编写使用
ASCII码插入加号或减号的预处理器。有很多解决方案，有些比其他解决方案更优雅。
这是我想出的解决方案。我想知道是否有更优雅或更有效的解决方案。
void addOne（unsigned int& i）{
int j = 1;
while（i& 1）{
i>> = 1;
j<< = 1;
}
= 1;
while！（j& 1）{
i<< = 1;
j>> = 1;
}
}
Q:
Write a C/C++ program that takes an unsigned integer and adds 1 to it
without using the plus or minus signs. Don''t worry about overflow issues. It
is cheating to use assembly commands, or to write a preprocessor that uses
ASCII codes to insert the plus or minus sign. There are many solutions, some
more elegant than others.
Here''s the solution I came up with. I''m wondering if there''s a solution that
is more elegant or efficient.
void addOne(unsigned int &i) {
int j = 1;
while (i & 1) {
i >>= 1;
j <<= 1;
}
i |= 1;
while !(j & 1) {
i <<= 1;
j >>= 1;
}
}
很好的尝试，但是关于风格，优先使用函数而不是
一个输入/输出参数，以及关于C ++ ，上面不应该编译：总是
编写的代码（除非重点是它没有编译）。
At为你做家庭作业的风险：
未签名的下一个（未签名的x）
{
if（x ==〜 0）{return 0; }
unsigned flipmask =〜0;
while（（x | flipmask）== ~0）
{
flipmask<< = 1;
}
返回x ^ ~flipmask;
}
陈述此解决方案所依赖的假设。
-
答：因为它弄乱了人们通常阅读文本的顺序。
问：为什么这么糟糕？
A：热门发布。
问：usenet上最烦人的事情是什么并在电子邮件中？
Good attempt, but regarding style, preferentially use a function rather than
an in/out argument, and regarding C++, the above shouldn''t compile: always
post code that compiles (except when the point is that it doesn''t compile).
At the risk of doing your HOMEWORK for you:
unsigned next( unsigned x )
{
if( x == ~0 ) { return 0; }
unsigned flipmask = ~0;
while( (x | flipmask) == ~0 )
{
flipmask <<= 1;
}
return x ^ ~flipmask;
}
State the assumptions that this solution relies on.
--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
在文章< Bt ************ @ read1.cgocable.net>中，Method Man< a@b.c>写道：
In article <Bt************@read1.cgocable.net>, Method Man <a@b.c> wrote:
问：
编写一个C / C ++程序，该程序采用无符号整数并加1，而不使用加号或减号。不要担心溢出问题。
（这实际上更容易处理无符号溢出，就像++
运算符一样，通过环绕而不是将其视为a不要
担心这个特殊情况。
这是我提出的解决方案。我想知道是否有更优雅或更有效的解决方案。
void addOne（unsigned int& i）{
int j = 1;
while（i& 1）{
i>> = 1;
j<< = 1;
}
= 1;
while！（j& 1）{
i<< = 1;
j>> = 1;
}
}
我有一个只使用一个循环的解决方案：
--------
/ *读者练习：
-找出并纠正故意引入的bug
（也就是说，不要把它作为你的作业而不用想一想
首先，否则你会失败）
-解释这个bug有什么影响以及为什么
-重构我的评论解释代码在做什么以及为什么
* /
unsigned long inc（unsigned long i）
{
unsigned long j = 1;
while（j）
{
i ^ = j;
if（！ （i& j））
返回i;
j<< = 1;
}
返回i;
}
--------
dave
-
Dave Vandervies dj ****** @ csclub.uwaterloo.ca 就像C一样，vi并不是无能为力。
Q:
Write a C/C++ program that takes an unsigned integer and adds 1 to it
without using the plus or minus signs. Don''t worry about overflow issues.
(It''s actually easier to treat unsigned overflow the same way the ++
operator does it, by wrapping around, than by treating it as a "Don''t
worry about this" special case.)
Here''s the solution I came up with. I''m wondering if there''s a solution that
is more elegant or efficient.
void addOne(unsigned int &i) {
int j = 1;
while (i & 1) {
i >>= 1;
j <<= 1;
}
i |= 1;
while !(j & 1) {
i <<= 1;
j >>= 1;
}
}
I have a solution that only uses one loop:
--------
/*Exercises for the reader:
-Find and correct the deliberately introduced bug
(that is, don''t hand this in as your homework without thinking about it
first, or you''ll fail)
-Explain what effect the bug has and why
-Reconstruct my comments explaining what the code is doing and why
*/
unsigned long inc(unsigned long i)
{
unsigned long j=1;
while(j)
{
i^=j;
if(!(i&j))
return i;
j<<=1;
}
return i;
}
--------
dave
--
Dave Vandervies dj******@csclub.uwaterloo.ca Just like C, vi is not incompetent-friendly.
我不同意。我和C和vi都很好。
--Dan Pop和Richard Heathfield在comp.lang.c
I disagree. I get on just fine with both C and vi.
--Dan Pop and Richard Heathfield in comp.lang.c
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