blocks|key|3609324|text|int+count_number_of_different_persons(run+results[])|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3609325|这并不能真正让你在数组上使用sizeof，因为数组会衰减成指针。|unstyled|offset|length|style|CODE|3609326|这|3609327|run+*run1+=+*(run+**)a;|3609328|看起来也很奇怪，不是吗？|3609329|run+*run1+=+(run*)a;|3609330|3609331|entityMap^0|0|E|6|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|W|8|@$G|X|H|Y|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|Z|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|10|8|@]|9|@]|A|$B|C]]|$1|O|3|P|5|F|7|11|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|12|8|@]|9|@]|A|$B|C]]|$1|S|3|-4|5|F|7|13|8|@]|9|@]|A|$]]|$1|T|3|-4|5|F|7|14|8|@]|9|@]|A|$]]]|U|$]]

<pre><code>int count_number_of_different_persons(run results[])
</code></pre>

This doesn't really let you use <code>sizeof</code> on the array, because array is decayed to pointer.

This

<pre><code>run *run1 = *(run **)a;
</code></pre>

also looks weird, shouldn't it be

<pre><code>run *run1 = (run*)a;
</code></pre>

?

blocks|key|5223190|text|一个问题是在name_compare中。试着这样做：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5223191|int+name_compare(const+void+*a,+const+void+*b)+
{
++++run+*run1+=+(run+*)a;
++++run+*run2+=+(run+*)b;
++++return+strcmp(run1->name,+run2->name);
}|code-block|syntax|javascript|5223192|entityMap^0|6|C|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|$]]

One problem is in <code>name_compare</code>. Try this instead:

<pre><code>int name_compare(const void *a, const void *b) 
{
 run *run1 = (run *)a;
 run *run2 = (run *)b;
 return strcmp(run1-&gt;name, run2-&gt;name);
}
</code></pre>

blocks|key|16363|text|检查以下代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|16364|正如@michel提到的，sizeof(+array+)提供指针的大小，而不是数组本身的大小，因为当传递array时，它被视为指针。因此，要么将元素数量发送到函数count_number_of_different_persons，要么定义一个元素数量的宏。希望这能有所帮助。:)。|16365|#include+<stdio.h>
#include+<stdlib.h>
#include+<string.h>

#define+NOE+3

struct+run
{
++++char+name[20];
};

typedef+struct+run+run;

int+name_compare+(const+void+*a,+const+void+*b+)
{
++++return+strcmp+(((run+*)a)->name,+((run+*)b)->name);
}

int+count_number_of_different_persons(run+results[],+int+noOfElements)
{
++++int+i=0;
++++qsort(results,+noOfElements,+sizeof+(run),+name_compare);
++++for+(i=0;+i<noOfElements;+i%2B%2B)
++++++++printf+("%25s\n",results[i].name);
}

int+main+(+int+argc,+char+*+argv[])
{
++++run+a,+b,+c;
++++run++arg[NOE];

++++strcpy+(a.name,+"love");
++++strcpy+(b.name,+"you");
++++strcpy+(c.name,+"i");
++++arg[0]+=+a;
++++arg[1]+=+b;
++++arg[2]+=+c;

++++count_number_of_different_persons(arg,+sizeof(arg)/sizeof(run));
};|code-block|syntax|javascript|16366|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|$]]

Check the following code:

As @michel mentioned, sizeof(array) provides size of the pointer, not the size of the array itself, as while passing array it is treated as a pointer. Hence either send the number of elements to the function count_number_of_different_persons or define a MACRO of number of elements. Hope this helps. :). 

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

#define NOE 3

struct run
{
 char name[20];
};

typedef struct run run;

int name_compare (const void *a, const void *b )
{
 return strcmp (((run *)a)-&gt;name, ((run *)b)-&gt;name);
}

int count_number_of_different_persons(run results[], int noOfElements)
{
 int i=0;
 qsort(results, noOfElements, sizeof (run), name_compare);
 for (i=0; i&lt;noOfElements; i++)
 printf ("%s\n",results[i].name);
}

int main ( int argc, char * argv[])
{
 run a, b, c;
 run arg[NOE];

 strcpy (a.name, "love");
 strcpy (b.name, "you");
 strcpy (c.name, "i");
 arg[0] = a;
 arg[1] = b;
 arg[2] = c;

 count_number_of_different_persons(arg, sizeof(arg)/sizeof(run));
};
</code></pre>

I am trying to sort a struct run array called results by a char, but when I print the array, nothing is sorted. Have a look at this:

<pre><code>struct run {
 char name[20], weekday[4], month[10];
 (And some more...)
};
typedef struct run run;

int name_compare(const void *a, const void *b) 
{
 run *run1 = *(run **)a;
 run *run2 = *(run **)b;
 return strcmp(run1-&gt;name, run2-&gt;name);
}

int count_number_of_different_persons(run results[])
{
 int i = 0;


 qsort(results, sizeof(results) / sizeof(run), sizeof(run), name_compare);

 for(i = 0; i &lt;= 999; i++)
 {
 printf("%s\n", results[i].name);
 }
 // not done with this function yet, just return 0
 return 0;
}
</code></pre>

The output from the above is just a list of names in the order they were originally placed

qsort of struct array not working

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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我尝试按char对名为results的struct run数组进行排序，但当我打印该数组时，没有排序。看看这个：struct run {  char name[20], weekday[4], month[10];  (And some more...)};typedef struct run run;int name...

问结构数组的Q排序不起作用
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