转换和朋友 [英] switch and friends
问题描述
嘿人，
有人可以解释一下这个片段是如何工作的吗？我在一场比赛中遇到了这个问题，这个问题在
时间真是空白。
实际上我后来跟踪了这个程序，但是我仍然怀疑为什么编译器似乎忽略了case，default ..。关键字。谢谢
预付款。
#include< stdio.h>
void func（）/ *经过一些追踪后我的代码* /
{
char str [] =" ++ c dna c evol I" ;;
int sz = sizeof（str）/ sizeof（char）;
int i = sz-1;
printf（" \ n"）;
开关（8）
{
案例2：while（i）
{
默认值：printf（"％c"，str [i--]）;}
}
}
int main（）
{
int i = 0;
/ *实际代码在比赛* /
开关（0）
{
案例1：for（; i< 5; i ++）
case 10：{printf（"％d"，i）;
while（i％3！= 0）
case 5：printf（"％） d"，++ i）;
默认值：printf（" *"）;
}
}
printf（" \ n\\\
\ n"）;
func（）;
scanf（"％d"）;
返回0;
}
Hey people,
Can somebody explain me how this fragment works ? I came across
this question in a competition and was really blank about this at the
time.
Actually I traced the program later but I still have doubts as to why
the compiler seems to neglect "case, default .. " keywords. Thanks in
advance.
#include <stdio.h>
void func() /*Code by me after some tracing */
{
char str[] = " ++c dna c evol I";
int sz = sizeof(str)/sizeof(char);
int i=sz-1;
printf("\n");
switch(8)
{
case 2:while(i)
{
default:printf("%c",str[i--]);}
}
}
int main()
{
int i=0;
/* Actual code in competition */
switch(0)
{
case 1: for(;i<5;i++)
case 10:{ printf("%d",i);
while(i%3!=0)
case 5: printf("%d",++i);
default: printf("*");
}
}
printf("\n\n\n");
func();
scanf("%d");
return 0;
}
推荐答案
gopala写道：
gopala wrote:
嘿人，
有人可以解释一下这个片段是如何工作的吗？我在一场比赛中遇到了这个问题，这个问题在
时间真是空白。
实际上我后来跟踪了这个程序，但是我仍然怀疑为什么编译器似乎忽略了case，default ..。关键字。谢谢
预付款。
#include< stdio.h>
void func（）/ *经过一些追踪后我的代码* /
{
char str [] =" ++ c dna c evol I" ;;
int sz = sizeof（str）/ sizeof（char）;
int i = sz-1;
printf（" \ n"）;
开关（8）
{
案例2：while（i）
{
默认值：printf（"％c"，str [i--]）;}
}
}
Hey people,
Can somebody explain me how this fragment works ? I came across
this question in a competition and was really blank about this at the
time.
Actually I traced the program later but I still have doubts as to why
the compiler seems to neglect "case, default .. " keywords. Thanks in
advance.
#include <stdio.h>
void func() /*Code by me after some tracing */
{
char str[] = " ++c dna c evol I";
int sz = sizeof(str)/sizeof(char);
int i=sz-1;
printf("\n");
switch(8)
{
case 2:while(i)
{
default:printf("%c",str[i--]);}
}
}
使用switch语句可以获得各种乐趣。我承认我经常
很难读取代码来破译它的作用，但是着名的
例子是Duff的设备：http：// en。 wikipedia.org/wiki/Duff''s_device
这段代码看起来像是使用类似的方法向后走过
a字符串来打印_secret_消息。
All sorts of fun can be had with switch statements. I admit I often
have a hard time reading the code to decipher what it does, but a famous
example is Duff''s Device: http://en.wikipedia.org/wiki/Duff''s_device
This code looks like it uses a similar method to walk backwards through
a string to print the _secret_ message.
gopala写道：
gopala wrote:
嘿人，
有人可以解释我怎么样这个片段有效吗？
Hey people,
Can somebody explain me how this fragment works ?
是吗？
Does it?
我遇到了这个问题在
时间，这个比赛真是空白。
I came across
this question in a competition and was really blank about this at the
time.
我希望它丢失，因为，至少，...
I hope it lost, because of, at least, ...
/ *实际代码在竞争中* /
/* Actual code in competition */
[...]
[...]
scanf（"％d"）;
scanf("%d");
5月4日上午8：39，gopala< krishna .... @ gmail.comwrote：
On May 4, 8:39 am, gopala <krishna....@gmail.comwrote:
嘿人们，
有人可以解释一下这个片段是如何工作的吗？我在一场比赛中遇到了这个问题，这个问题在
时间真是空白。
实际上我后来跟踪了这个程序，但是我仍然怀疑为什么编译器似乎忽略了case，default ..。关键字。谢谢
预付款。
#include< stdio.h>
void func（）/ *经过一些追踪后我的代码* /
{
char str [] =" ++ c dna c evol I" ;;
int sz = sizeof（str）/ sizeof（char）;
int i = sz-1;
printf（" \ n"）;
开关（8）
{
案例2：while（i）
{
默认值：printf（"％c"，str [i--]）;}
}
}
int main（）
{
int i = 0;
/ *竞赛中的实际代码* /
开关（0）
{
案例1：for（; i< 5; i ++）
案例10：{printf（"％d"，i）;
while（i％3！= 0）
案例5：printf（％d，++ i）;
默认值：printf（" *"）;
}}
printf（" \ n\\\
\ n"）;
func（）;
scanf（"％d" ）;
返回0;
} - 隐藏引用的文字 -
- 显示引用文字 -
Hey people,
Can somebody explain me how this fragment works ? I came across
this question in a competition and was really blank about this at the
time.
Actually I traced the program later but I still have doubts as to why
the compiler seems to neglect "case, default .. " keywords. Thanks in
advance.
#include <stdio.h>
void func() /*Code by me after some tracing */
{
char str[] = " ++c dna c evol I";
int sz = sizeof(str)/sizeof(char);
int i=sz-1;
printf("\n");
switch(8)
{
case 2:while(i)
{
default:printf("%c",str[i--]);}
}
}
int main()
{
int i=0;
/* Actual code in competition */
switch(0)
{
case 1: for(;i<5;i++)
case 10:{ printf("%d",i);
while(i%3!=0)
case 5: printf("%d",++i);
default: printf("*");
}}
printf("\n\n\n");
func();
scanf("%d");
return 0;
}- Hide quoted text -
- Show quoted text -
请提及比赛中确切要求的内容
Ciao，
AK
Please mention what was exactly asked in the competition
Ciao,
AK
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