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POInfinite loop scanf-function
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copied!<p>I am learning c and understand that this language is low-level and in this context lacks exception handling. </p> <p>I made a simple program where the user choose among some alternatives from a menu. Its just that simple!</p> <p>The program is divided into a few methods - one of the methods waits for the user to press a key - an integer is expected. Then return this integer to another method which holds a switch-structure. </p> <p>The problem arises when a character is pressed - in most cases an infinite loop of the else-block is started. </p> <p><em>You must choose an alternative 0 - 2. Please try again :-)</em></p> <p><em>You must choose an alternative 0 - 2. Please try again :-)</em></p> <p><em>You must choose an alternative 0 - 2. Please try again :-)</em></p> <p>...... and so on</p> <p>I do not actually know how to solve this. I have tried to use the return value from the scanf-function without success. I have also tried to pass a character (instead of integer) as an argument to the scanf-function - also without success.</p> <p>Any suggestion how to handle this problem? </p> <pre><code>#include <stdio.h> #include <stdlib.h> void menu(); void runSelection(int selection); int getSelection(); int pause(); int main(void) { do{ menu(); runSelection(getSelection()); }while(pause()); return 0; } int pause() { int c; printf("\n\nPress enter to continue!"); fflush(stdout); /* flush inputstream */ while((c = getchar()) != '\n' && c != EOF); getchar(); return 1; } void menu() { puts(" * * * * * * M E N U * * * * * * *"); puts("1. Do something 1"); puts("2. Do something 2"); puts("3. Do something 3"); fflush(stdout); } void runSelection(int selection) { switch (selection) { case 0: puts("you pressed 0"); break; case 1: puts("you pressed 1"); break; case 2: puts("you pressed 2"); break; } } int getSelection() { int key; int true = 0; do { scanf("%d", &key); if (key >= 0 && key <=2) { true = 1; } else { puts("You must choose an alternative 0 - 2. Please try again :-)"); fflush(stdout); } } while (true == 0); return key; } </code></pre>

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