Databases
StackOverflow2013
Postsdbo
POWriting a comparision function for qsort
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWriting a comparision function for qsort
    primarykey
    data
    text
    <p>I'm writing a comparision function that compares and organizes names by ascending order of last name and if both last names are the same, descending order of first names. The function I have right now will not do that.</p> <p>Here is the function:</p> <pre><code>int namecmp(const void *p, const void *q) { const name *pp = p; const name *qq = q; int n; if((n = strcmp(pp-&gt;last, qq-&gt;last)) != 0) return n; return qq-&gt;first - pp-&gt;first; } </code></pre> <p>I am trying to organize a dynamic array of structures, here are my structures.</p> <pre><code>typedef struct { char last[NAMESIZE]; char first[NAMESIZE]; }name; typedef struct { int id; name name; float score; }record; typedef struct { record *data; /* the dynamic array */ size_t nalloc; /* number of records allocated */ size_t nused; /* number of records in use */ } record_list; </code></pre> <p>and here is how qsort is called.</p> <pre><code>qsort(list-&gt;data, list-&gt;nused, sizeof(list-&gt;data[0]), namecmp); </code></pre> <p>Any help would be appreciated.</p> <p>EDIT: I did what you suggested now i have the wrong output.</p> <p>my output is:</p> <pre><code>3456789 Burns, Monty: 100.00 4567890 Simpson, Lisa: 95.00 1234567 Simpson, Homer: 35.50 6666666 Simpson, Bart: 45.00 2345678 Flanders, Ned: 99.50 </code></pre> <p>EDIT 2:</p> <p>How i store string into the structure.</p> <pre><code> if(sscanf(line,"%s", lastname) == 1) { if(strlen(lastname) &lt; NAMESIZE) { lastname[0] = toupper((int)lastname[0]); strcpy(rec-&gt;name.last, lastname); break; } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USuser798774
    1. USuser798774
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. COwhy do you think you need a strcmp for last name, but not first?
      singulars
      1. POWriting a comparision function for qsort
      1. USAShelly
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload