entityMap|blocks|key|4l61g|text|您正在交换本地指针变量，这是毫无意义的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1aib3|您需要交换指针所指向的char：|offset|length|style|CODE|2rltg|++++for(j=0;j<=(len-2)/2;j%2B%2B)
++++{
++++++++char+t,+*el,+*el2;
++++++++el+=+(strings[i]+%2B+j);
++++++++el2+=+(strings[i]%2B(len+-j-1));
++++++++t+=+*el2;
++++++++*el2+=+*el;
++++++++*el+=+t;
++++}|code-block|syntax|javascript|9fjm^0|0|B|4|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|O|9|@]|A|@]|B|$]]|$2|C|4|D|6|7|8|P|9|@$E|Q|F|R|G|H]]|A|@]|B|$]]|$2|I|4|J|6|K|8|S|9|@]|A|@]|B|$L|M]]|$2|N|4|-4|6|7|8|T|9|@]|A|@]|B|$]]]]

You're swapping local pointer variables, which is pointless.

You need to swap the <code>char</code>s the pointers point to:

<pre><code> for(j=0;j&lt;=(len-2)/2;j++)
 {
 char t, *el, *el2;
 el = (strings[i] + j);
 el2 = (strings[i]+(len -j-1));
 t = *el2;
 *el2 = *el;
 *el = t;
 }
</code></pre>

entityMap|blocks|key|a3pqh|text|你什么也改变不了。我建议使用交换函数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|d5khe|void+swap(char+*a,+char+*b)
{
++++char+tmp+=+*a;
++++*a+=+*b;
++++*b+=+tmp;
}|code-block|syntax|javascript|c071r|然后在内部循环中：|613cm|for(j=0;j<=(len-2)/2;j%2B%2B)
{
++++swap(strings[i]+%2B+j,+strings[i]%2B(len+-j-1));
}|fpvmc^0|0|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|M|9|@]|A|@]|B|$]]|$2|C|4|D|6|E|8|N|9|@]|A|@]|B|$F|G]]|$2|H|4|I|6|7|8|O|9|@]|A|@]|B|$]]|$2|J|4|K|6|E|8|P|9|@]|A|@]|B|$F|G]]|$2|L|4|-4|6|7|8|Q|9|@]|A|@]|B|$]]]]

You're not changing anything. I'd recommend using a swap function:

<pre><code>void swap(char *a, char *b)
{
 char tmp = *a;
 *a = *b;
 *b = tmp;
}
</code></pre>

And then in the inner loop:

<pre><code>for(j=0;j&lt;=(len-2)/2;j++)
{
 swap(strings[i] + j, strings[i]+(len -j-1));
}
</code></pre>

entityMap|blocks|key|99j8n|text|在main()函数中就地执行字符串反转既麻烦又容易出错。相反，您应该编写一个简单的函数并使用它：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|dujs2|以下是一个经过修正和简化的版本：|1jhro|#include+<stdio.h>
#include+<stdlib.h>
#include+<string.h>

char+*str_reverse(char+*s)+{
++++for+(size_t+i+=+0,+j+=+strlen(s);+i+<+j--;+i%2B%2B)+{
++++++++char+t+=+s[i];
++++++++s[i]+=+s[j];
++++++++s[j]+=+t;
++++}
++++return+s;
}

int+main()+{
++++int+x,+i;

++++printf("How+many+strings+you+want+to+enter:\n");
++++if+(scanf("%25d",+&x)+!=+1+%7C%7C+x+<=+0+%7C%7C+x+>+1000)+{
++++++++printf("Invalid+number:+%25d\n",+x);
++++++++return+1;
++++}

++++char+*strings[x],+string[50];

++++for+(i+=+0;+i+<+x;+i%2B%2B)+{
++++++++if+(scanf("+%2549[%5E\n]",+string)+!=+1)+{
++++++++++++printf("Premature+end+of+file\n");
++++++++++++return+1;
++++++++}
++++++++//+use+strdup+to+allocate+string+copies.
++++++++//+strdup+is+a+Posix+standard+function
++++++++//+if+your+system+does+not+have+it,+it+is+easy+to+implement.
++++++++strings[i]+=+strdup(string);
++++}
++++printf("Entered+strings+are:\n");
++++for+(i+=+0;+i+<+x;+i%2B%2B)+{
++++++++printf("%25s\n",+strings[i]);
++++}
++++//+Reverse+strings
++++for+(i+=+0;+i+<+x;+i%2B%2B)+{
++++++++str_reverse(strings[i]);
++++}
++++printf("Reversed+strings:\n");
++++for+(i+=+0;+i+<+x;+i%2B%2B)+{
++++++++printf("%25s\n",+strings[i]);
++++}
++++return+0;
}|code-block|syntax|javascript|a8rvi^0|1|6|0|0|0^^$0|$]|1|@$2|3|4|5|6|7|8|O|9|@$A|P|B|Q|C|D]]|E|@]|F|$]]|$2|G|4|H|6|7|8|R|9|@]|E|@]|F|$]]|$2|I|4|J|6|K|8|S|9|@]|E|@]|F|$L|M]]|$2|N|4|-4|6|7|8|T|9|@]|E|@]|F|$]]]]

Performing string reversal in place in your <code>main()</code> function is cumbersome and error prone. You should instead write a simple function and use it:

Here is a corrected and simplified version:

<pre class="lang-c prettyprint-override"><code>#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;

char *str_reverse(char *s) {
 for (size_t i = 0, j = strlen(s); i &lt; j--; i++) {
 char t = s[i];
 s[i] = s[j];
 s[j] = t;
 }
 return s;
}

int main() {
 int x, i;

 printf("How many strings you want to enter:\n");
 if (scanf("%d", &amp;x) != 1 || x &lt;= 0 || x &gt; 1000) {
 printf("Invalid number: %d\n", x);
 return 1;
 }

 char *strings[x], string[50];

 for (i = 0; i &lt; x; i++) {
 if (scanf(" %49[^\n]", string) != 1) {
 printf("Premature end of file\n");
 return 1;
 }
 // use strdup to allocate string copies.
 // strdup is a Posix standard function
 // if your system does not have it, it is easy to implement.
 strings[i] = strdup(string);
 }
 printf("Entered strings are:\n");
 for (i = 0; i &lt; x; i++) {
 printf("%s\n", strings[i]);
 }
 // Reverse strings
 for (i = 0; i &lt; x; i++) {
 str_reverse(strings[i]);
 }
 printf("Reversed strings:\n");
 for (i = 0; i &lt; x; i++) {
 printf("%s\n", strings[i]);
 }
 return 0;
}
</code></pre>

The problem is to reverse all the strings in an array of pointers to strings. I wrote the following code for the same. After showing the entered strings the code is not able to reverse the strings. I have tried changing <code>el</code> and <code>el2</code> character pointers to characters also, but to no use. Please help me with this.

<pre><code>#include &lt;stdio.h&gt;
#include &lt;string.h&gt;
#include &lt;stdlib.h&gt;

int main() {
 int x, i, length, len, j;
 printf("How many strings you want to enter:\n");
 scanf("%d", &amp;x);
 char *strings[x], string[50], *p, *t, *el, *el2;
 for (i = 0; i &lt; x; i++) {
 scanf(" %49[^\n]", string);
 length = strlen(string);
 p = (char *)malloc(length + 1);
 strcpy(p, string);
 strings[i] = p;
 }
 printf("Entered strings are:\n");
 for (i = 0; i &lt; x; i++) {
 printf("%s\n", strings[i]);
 }
 printf("Reversed strings :\n");
 for (i = 0; i &lt; x; i++) {
 len = strlen(strings[i]);
 for (j = 0; j &lt;= (len - 2) / 2; j++) {
 el = (strings[i] + j);
 el2 = (strings[i] + (len - j - 1));
 t = el2;
 el2 = el;
 el = t;
 }
 }
 for (i = 0; i &lt; x; i++) {
 printf("%s\n", strings[i]);
 }
 return 0;
}
</code></pre>

Why the code is not reversing the strings?

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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问题是反转指向字符串的指针数组中的所有字符串。我为同样的目的写了下面的代码。在显示输入的字符串之后，代码无法反转这些字符串。我也尝试过将el和el2字符指针改为字符，但都没有用。请帮我弄一下这个。 #include <stdio.h>#include <string.h>#include <stdlib.h>int ...

问为什么代码没有颠倒字符串？
EN

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问为什么代码没有颠倒字符串？EN