blocks|key|4027577|text|您的代码只修改已经大写的字母，并将它们转换为“谁知道什么”(嗯，我相信您可以使用ASCII表)。如果要对小写字母进行操作，则需要更改if条件：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4027578|if+(str[i]+>=+'a'+&&+str[i]+<=+'z')+|code-block|syntax|javascript|4027579|entityMap^0|1U|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Your code only modifies already-uppercase letters, and turns them into who-knows-what (well, I'm sure you could figure out with an ASCII table). If you want to operate on lowercase letters, you need to change your <code>if</code> condition:

<pre><code>if (str[i] &gt;= 'a' &amp;&amp; str[i] &lt;= 'z') 
</code></pre>

blocks|key|247111|text|你为什么要重新发明轮子？ctype.h是你的朋友|type|unstyled|depth|inlineStyleRanges|entityRanges|data|247112|使用toupper(int)方法。就像这样|247113|char*+stoupper(char+str[]);

char+str[100]=+"uppercase";

printf("%25s"+,+stoupper(str));+//+Test+to+make+sure+it+is+working+

char*+stoupper(char+str[])
{+
++++++int+i+=+0;+

++++++while(str[i])+
++++++{+
++++++++++str[i]=toupper(str[i]);
++++++++++i%2B%2B;+
++++++}
++++++return+str;
}++|code-block|syntax|javascript|247114|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

why are you reinventing the wheel? ctype.h is your friend

Use the toupper(int) method. Something like

<pre><code>char* stoupper(char str[]);

char str[100]= "uppercase";

printf("%s" , stoupper(str)); // Test to make sure it is working 

char* stoupper(char str[])
{ 
 int i = 0; 

 while(str[i]) 
 { 
 str[i]=toupper(str[i]);
 i++; 
 }
 return str;
} 
</code></pre>

blocks|key|247116|text|我认为你的if条件应该是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|247117|if(str[i]+>=+'a'+&&+str[i]+<=+'z')+|code-block|syntax|javascript|247118|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I think your if condition should be:

<pre><code>if(str[i] &gt;= 'a' &amp;&amp; str[i] &lt;= 'z') 
</code></pre>

blocks|key|2636889|text|需要更改if语句中的条件|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2636890|2636891|+if(stri+>=+'A‘&+stri+<=+'Z')|blockquote|2636892|2636893|2636894|我可以建议另一种方法，将大写字母改为小写字母，反之亦然|2636895|char*+stoupper(char+str[])
{+
++++++for(int+i=0;i<strlen(str);i%2B%2B)
++++++++++if(!(str[i]>='A'&&str[i]<='Z')){
++++++++++++++str[i]=str[i]%5E'+';
++++++++++}

++++++return+str;
}+|code-block|syntax|javascript|2636896|此方法之所以有效，是因为|2636897|小写字符ASCII值XOR‘’的ASCII值=同一字符的大写ASCII值|2636898|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|V|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|W|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|A|$]]|$1|G|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Z|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|10|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|11|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|12|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|T|$]]

your condition in if statement needs to be changed 

<blockquote>
 if(str[i] >= 'A' &amp;&amp; str[i] &lt;= 'Z') 
</blockquote>

May I suggest another way to change Uppercase to lowercase and vice-versa

<pre><code>char* stoupper(char str[])
{ 
 for(int i=0;i&lt;strlen(str);i++)
 if(!(str[i]&gt;='A'&amp;&amp;str[i]&lt;='Z')){
 str[i]=str[i]^' ';
 }

 return str;
} 
</code></pre>

this method works because

[ASCII value of a lowercase character] XOR [ASCII value of ' '] =[ASCII value of that same character in UPPERCASE ]

I've written this function to convert a lowercase str that is preset into it's uppercase variant. I've tried every different configuration I know that converts lower case to uppercase, however when I print it. It still ends up in lower case. So I am a tad Stuck. 

<pre><code>char* stoupper(char str[]);

char str[100]= "uppercase";

printf("%s" , stoupper(str)); // Test to make sure it is working 

char* stoupper(char str[])
{ 
 int i = 0; 

 while(str[i] != '\0') 
 { 
 if(str[i] &gt;= 'A' &amp;&amp; str[i] &lt;= 'Z') 
 str[i] = str[i] + ('A' - 'a'); 
 i++; 
 }
 return str;
} 

/* I've tried various variations of this function this is just the one i had first */ 
</code></pre>

lower case to Uppercase function - C

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我已经编写了这个函数来将预设的小写字符串转换为它的大写变体。我已经尝试了我所知道的每种不同的配置，这些配置将小写转换为大写，但是当我打印它时。它仍然以小写结尾。所以我有点卡住了。char* stoupper(char str[]);char str[100]= "uppercase";printf("%s" , sto...

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