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POHow validate user input when the expected value is of type int and the entered value is not of type int?
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copied!<p>I have the following code:</p> <pre><code>#include <stdio.h> #define MIN 0 #define MAX 9 int main() { int n; while (1) { printf("Enter a number (%d-%d) :", MIN, MAX); scanf("%d", &n); if (n >= MIN && n <= MAX) { printf("Good\n"); } else { printf("Damn you!\n"); break; } } return 0; } </code></pre> <p>The above code works as expected as long as the user inputs an integer value. For example, </p> <pre><code>$ ./a.out Enter a number (0-9) :15 Damn you! $ ./a.out Enter a number (0-9) :5 Good Enter a number (0-9) :3 Good Enter a number (0-9) :-1 Damn you! $ ./a.out </code></pre> <p>But, when the user enters any unexpected input (like <code><up-arrow></code> - which is <code>^[[A</code>, or any string like <code>abc</code> or <code>abc def</code>, etc), it fails and goes in to an infinite loop.</p> <pre><code>$ ./a.out Enter a number (0-9) :2 Good Enter a number (0-9) :^[[A Good Enter a number (0-9) :Good Enter a number (0-9) :Good Enter a number (0-9) :Good Enter a number (0-9) :Good Enter a number (0-9) :Good Enter a number (0-9) :Good ^C </code></pre> <p>One thing to note: when the use enters <code><up-arrow></code> for the first time, it works as expected! For example, </p> <pre><code>$ ./a.out Enter a number (0-9) :^[[A Damn you! $ </code></pre> <p>Why is this odd behavior? How should we handle the case where user enters something that is unappropriate?</p>

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