使用strtod

谢谢 解决方案 coder写道： 嗨专家， strtod的以下用法是好的（p是一个字符指针）： value = strtod（p，& p）; 是否有可能引起未定义的行为？ 或者我应该使用临时指针然后将其值分配给p？ 只要你绕过strtod的任何宏观 定义，你就可以这样做： value =（strtod）（p，& p）; 但是暂时使用它会更干净。 2月18日，10：47 pm，Harald van D？3k < true ... @ gmail.comwrote： coder写道： < snip> 感谢回复，Harald。 你可以这样做只要你绕过strtod的任何可能的宏定义： value =（strtod）（p，& p）; 我没有得到。你能解释一下吗？ 但是使用临时工具会更干净。 coder写道： 嗨专家， strtod的以下用法是否正确（p是一个字符指针）： value = strtod（p，& p）; 是否有可能引起未定义的行为？ 或者我应该使用临时指针然后将其值分配给p？ 你应该使用临时的，而不是因为未定义的 行为（但请参阅Harald van D？3k'的回复），但是因为 当你检查 的错误时，你需要原始指针的值。在strtod（p，& q）之后，条件p == q意味着 strtod（）无法转换任何输入。如果你用写strtod（p，& p）你将无法进行测试。 - Eric Sosman es*****@acm-dot-org.inva lid Hi experts,Is the following usage of strtod okay (p is a char pointer): value = strtod(p, &p); Is it possible that this would evoke undefined behaviour?Or should I use a temporary pointer and then assign its value to p? Thanks 解决方案 coder wrote:Hi experts,Is the following usage of strtod okay (p is a char pointer):value = strtod(p, &p);Is it possible that this would evoke undefined behaviour?Or should I use a temporary pointer and then assign its value to p?You are allowed to do this as long as you bypass any possible macrodefinition of strtod: value = (strtod) (p, &p); But it would be cleaner to just use a temporary. On Feb 18, 10:47 pm, "Harald van D?3k" <[email protected]:coder wrote: <snip> Thanks for the reply, Harald. You are allowed to do this as long as you bypass any possible macrodefinition of strtod:value = (strtod) (p, &p);I didn''t get that. Can you please explain a little more? But it would be cleaner to just use a temporary. coder wrote:Hi experts,Is the following usage of strtod okay (p is a char pointer):value = strtod(p, &p);Is it possible that this would evoke undefined behaviour?Or should I use a temporary pointer and then assign its value to p?You should use a temporary, not because of undefinedbehavior (but see Harald van D?3k''s response), but becauseyou will need the original pointer''s value when you checkfor errors. After strtod(p, &q), the condition p==q meansstrtod() was unable to convert any of the input. If youwrite strtod(p, &p) you will be unable to make the test. --Eric Sosman es*****@acm-dot-org.invalid 这篇关于使用strtod的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！