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POscanf gets skipped, even with safeties (getchar())
 

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  1. POscanf gets skipped, even with safeties (getchar())
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    <p>I know this question gets asked a hundred times over, and I've scoured all of the possibilities, but I guess I'm not adept enough to know where this problem lies. I'm programming a program where I need to fill a struct with data (ints and strings). The first time I tried it it skipped over everything but the first one, but I didn't panic since I remembered from class I needed to use <code>fflush(stdin)</code> to overcome this. Websites I've searched vote against use of <code>fflush(stdin)</code>, since it has undefined behaviour. They say using <code>getchar()</code> would eat the extra newline, thus fixing the problem. Hence my code:</p> <pre><code>int manNode(){ Item *p; int helper; p = (Item*)malloc(sizeof(Item)); printf("Welk type? (Taak:1, Examen:2, Voordracht:3)\n"); scanf("%u",&amp;helper); //selecting an itemtype if (helper &lt; 1 || helper &gt; 3) { printf("wrong value, please try again"); return 0; } getchar(); //I've just put getchars everywhere for safety. p-&gt;entrytype = helper-1; helper = 0; printf("Vul een naam in:\n"); scanf("%s", p-&gt;name); //this one fills in fine getchar(); printf("Vul een vaknaam in: \n"); scanf("%s", p-&gt;course); //this one gets skipped if I type more than one letter in the last scanf() getchar(); printf("Vul een starttijd in:\n"); //From here on out everything gets skipped p-&gt;start = getTijd(); checkTijd(p-&gt;start); printf("Vul een eindtijd in: \n"); p-&gt;end = getTijd(); checkTijd(p-&gt;end); </code></pre> <p>I know it's a bit messy, but focus on the scanfs and getchars. <code>getTijd()</code> also has a couple of scanfs in it that scan for integers, they also get skipped. I don't know where to go from here. (The code isn't incomplete, the rest is just irrelevant)</p>
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    1. USGhijs Kilani
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    1. COCan you show the structure `Item`?
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      1. USIshmeet
    2. CO`scanf` is about the worst possible parsing tool available in C because it tries to do two tasks (read input and break it into pieces) and when the pieces aren't exactly as expected it leaves the input stream in a hard-to-determine state. `fgets/sscanf` makes for a much more robust division of labor.
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      1. USmsw
    3. COYou have to check that `scanf()` succeeds every time you use it. When it goes wrong, it stays wrong. You should error check the `getchar()` functions. You should also debug by printing the value you just read, to make sure you got what you thought you got.
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      1. USJonathan Leffler
 

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