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工作学习 / IT技术讨论 / 问题讨论,考考你的C语言(a lillte bit more than that)知识很有趣哟
-eagle_no1(瞎起哄);
2003-6-14
{573}
(#1239588@0)
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The code can pass compilation. The result is e. unexpectedThe root-cause of the bug is the priority of "[]" is greater than "++". That results in sum = aa[20]+aa[19]+...
To avoid the operator priority error, I would suggest modify the code in simple way:
{
i --;
sum += aa[i];
}
aa[MAX_LEN] is acceptable in most popular compliers, but it may not be passed in old C compiler like C80.
-jami(jami);
2003-6-14
{359}
(#1239620@0)
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great! because you mentioned the compiler,Butwhat is the value of the aa[20]? is it consistant or just random?
-eagle_no1(瞎起哄);
2003-6-14
{67}
(#1239629@0)
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aa[20] would be located in the position of the space for int i=20 in the used stack.I'm sure its value should be 20 prior to do i--. Therefore, the sum is supposed to be 20.
-jami(jami);
2003-6-14
{90}
(#1240310@0)
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glad to discuss with you, actually I am confussed now, some compiler's behavior is too strange!!
-eagle_no1(瞎起哄);
2003-6-14
{6664}
(#1240400@0)
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exactly. your outcome is correct. I've confirmed it in Borland C++.As to BC compiler, the stack map is as follow:
low addr: i = 20
aa[0]...[20]
pad = 2
sum = 0
return address
high addr ...
aa[20]'s location in memory points to the space of pad. That's why the sum should be 2 all the time.
However, the result depends on the C compiler for the location of aa[20].
-jami(jami);
2003-6-15
{461}
(#1240663@0)
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oh, really? shakehand!
-eagle_no1(瞎起哄);
2003-6-15
(#1240773@0)
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大家平时是靠调试找出这些错误呢？还是光看源码就行了，这就太牛了！
-m30(m30);
2003-6-14
(#1240346@0)
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experience pus debuging
-eagle_no1(瞎起哄);
2003-6-14
(#1240411@0)
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有什么意义啊! 30岁以后还有为代码技巧和识别编译错误自豪的吗?
-needacar123(car);
2003-6-14
(#1240417@0)
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just technical discussion , no thing more, OK?
-eagle_no1(瞎起哄);
2003-6-14
(#1240434@0)
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OK,OK,OK.我跟M30说话呢,我不掺和你的technical discussion .
-needacar123(car);
2003-6-14
(#1240456@0)
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误会，误会，原来你们认识， 接着骂，接着骂。。我的意思是”只是技术讨论而已(当然是低级技术)，没有自豪的意思，是吗！“， 言不达意，见谅，见谅！
-eagle_no1(瞎起哄);
2003-6-15
{95}
(#1240501@0)
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我根本不认识他啊
-m30(m30);
2003-6-15
(#1240775@0)
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To m30:from you old posts, I found you graduated form an U. in wuhan, probably we know each other. I came from wuhan (HUST when 6.4)
-eagle_no1(瞎起哄);
2003-6-15
{126}
(#1240783@0)
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啊，有人在暗中收集我的信息啊？可怕！HUST too。不过到此为止，别再追问细节了啊？见同学情更怯啊！
-m30(m30);
2003-6-15
(#1240787@0)
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sorry! :-(
-eagle_no1(瞎起哄);
2003-6-15
(#1240789@0)
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看来以后我要做个好人了，这儿还有同学在盯着呢！
-m30(m30);
2003-6-15
(#1240793@0)
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我算是知道了什么是“自作多情”兄弟，没事，接着当坏人。
噢，别忘了，下次丢人显眼的时候，别说是HUST的 。。。就说你是。。。。武大的 ：P
-eagle_no1(瞎起哄);
2003-6-15
{103}
(#1240822@0)
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.呸，你一肚子坏水。偶看见就宣传他是HUST的。：））
-henhen(哼哼,找工ing...);
2003-6-15
{48}
(#1240837@0)
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:-(别台举他呀，大姐，？啊！ 我知道你的难处了，下回就说你没读过书不就得了。 ：-(
-eagle_no1(瞎起哄);
2003-6-15
{76}
(#1240850@0)
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:-(说偶没读过书倒是真的。
-henhen(哼哼,找工ing...);
2003-6-15
{22}
(#1240853@0)
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don't be sad, lady.just kidding LA
-eagle_no1(瞎起哄);
2003-6-15
(#1240862@0)
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我知道你是UofW的，我们都不要互相结发了，好吧？
-m30(m30);
2003-6-15
(#1240865@0)
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正中我的痛处
-tztz(退休老团长);
2003-6-15
(#1240794@0)
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If you folks are genuinely up to improve your C skills. Go get a book by Sun Microsystems' Peter Van Der Linden, you'll be amazed how deep the C world is.
-hairypotter(HP);
2003-6-15
(#1240826@0)
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Peter's web site.
-hairypotter(HP);
2003-6-15
(#1240838@0)
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Sample question from the book: why Halloween = Christmas?
-hairypotter(HP);
2003-6-15
(#1240842@0)
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My trouble is "why Halloween !=Christmas" see #1240400
-eagle_no1(瞎起哄);
2003-6-15
(#1240856@0)