...prevent my C program from accepting alpha entries...

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Question by redmike
Submitted on 5/10/2004
Related FAQ: comp.lang.c FAQ list Table of Contents
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How do I prevent my C program from accepting alpha entries for a calculation that wants only integers? If I type in a letter, it does the calculation as if I entered the number 2.

Answer by basti
Submitted on 8/20/2004
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maybe a code snippet would help...

Answer by tinku
Submitted on 2/21/2005
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to avoid alpha entries, u have to check the ASCII value of 0-9. if it is not then ask the use to again enter the value

Answer by Manos Theocharopoulos
Submitted on 4/28/2005
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Use getchar() instead of scanf() and check for the ASCII code of the character.They range between 48 for 0 and 57 for 9. Or use the Macro isdigit.

Answer by kakapada
Submitted on 9/5/2005
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Just check the input with its ASCII value and if the ASCII does not fall into the permissible range then just discard the input.Here is an example ......... .......... while(1) { scanf("%d",&num); /num is integer/ ch = num; /ch is character/ if ( ch>= 48 && ch<= 58) break; } ......... ......... 48 is the ASCII value for 0 and 58 is for 9

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