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POHow can I check if the user has entered valid value?
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  1. POHow can I check if the user has entered valid value?
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    copied!<p>I'm writing a project and I have to check if the user has entered a valid value for specific things. For example, first case is to check whether he inputted an integer, which is no longer than 6 length and >0. I am working with struct, so my code is this:</p> <pre><code>#include &lt;iostream&gt; using namespace std; int dolzina_int(int vlez); int main() { struct pole{ int sifra; // sifra na artiklot string opis; // opis na artiklot float cena; // edinecna cena int vlez_kol; // vlezna kolicina int izlez_kol; // izlezna kolicina float dan_stapka; // danocna stapka float iznos; // iznos int datum; // datum na vlez i izlez (GGMMDD) }artikli[100]; // maksimalen broj na artikli e 100 for (int i = 0; i &lt; 5; i++){ cin &gt;&gt; artikli[i].sifra; while(!(cin &gt;&gt; artikli[i].sifra) || (artikli[i].sifra &lt; 0 || (dolzina_int(artikli[i].sifra) &gt; 6))) { cout &lt;&lt; "Error" &lt;&lt; endl; cin.clear(); std::cin.ignore(std::numeric_limits&lt;std::streamsize&gt;::max(), '\n'); } } return 0; } // funkcija za dolzina na integer int dolzina_int(int vlez){ int dolzina = 1; while(vlez &gt; 0){ dolzina++; vlez /= 10; } return dolzina; } </code></pre> <p>So, my code seems to work, the first part, it does check if it's >6 or &lt;0, but the second else if, it doesn't work properly to check if it's an integer or not. So my question is the following, how can i make sure that it's an integer value that the user enters and how can I make sure the length of integer is not >6 or the value is &lt;0 and meanwhile, if it is, to make him re-enter it, and also check the newly entered value, as my code doesn't do that currently.</p> <pre><code>for (int i = 0; i &lt; 5; i++){ artikli[i].sifra = 1; do{ cout &lt;&lt; "Enter a code: "; while(!(cin &gt;&gt; artikli[i].sifra)){ cin.clear(); cin.ignore(); cout &lt;&lt; "Invalid entry. Enter a new value: "; } }while(artikli[i].sifra &gt; 0 &amp;&amp; dolzina_int(artikli[i].sifra) &gt; 6); } </code></pre>
 

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