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Top Forums Programming Clear standard input buffer for C program in Linux Post 302912420 by Abhishek_kumar on Friday 8th of August 2014 05:48:55 AM
Old 08-08-2014
Ubuntu Clear standard input buffer for C program in Linux

Hello friends! i am writing a code in which i take inputs (numbers) from user and count the total number of positive, negative and zeros entered. I need to clear my standard input buffer before scanf() command. My compiler is completely ignoring the fflush(stdin) command. its not even showing any error!. I am using Linux(ubunto) platform. Help!
Code:
#include<stdio.h>
int main()
{
	int pos=0,neg=0,zeros=0;
	float num;
	char ans='y';
	while(ans=='y')
	{
		printf("Enter a number : ");
		scanf("%f",&num);
		if(num>0)
		{
			pos++;
		}
		else if(num<0)
		{
			neg++;
		}		
		else
		{
			zeros++;
		}		
		
		printf("Wanna enter another number ? (y/n)\n");
		fflush(stdin);			
		scanf("%c",&ans);			
		if(ans=='n')
		{
		printf("positive number : %d \n Negative numbers : %d \n Zeros : %d",pos,neg,zeros);
		}

	}
return 0;
}


Last edited by Abhishek_kumar; 08-08-2014 at 02:27 PM..
 

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rpmatch(3)						     Library Functions Manual							rpmatch(3)

NAME
rpmatch - Determines whether a response is affirmative or negative LIBRARY
Standard C Library (libc.a) SYNOPSIS
#include <stdlib.h> int rpmatch( const char *response); PARAMETERS
User input entered in response to a question that requires an affirmative or negative answer. DESCRIPTION
The rpmatch() function determines whether the string value of the response parameter matches the affirmative or negative response expres- sion as specified by the LC_MESSAGES category in the program's current locale. Both response expressions, defined in the locale, may be extended regular expressions. A possible value of the affirmative expression, yesexpr, for a English-language locale is "^([yY]|[yY][eE][sS])". This expression will match any value of the response parameter that has consists of the letter Y (in uppercase or lowercase) or the letters YES (in any mixture of uppercase and lowercase letters). EXAMPLES
The following example requests a response from the user and uses the rpmatch() function to determine if the response is affirmative or neg- ative. #include <stdlib.h> #include <stdio.h> #include <locale.h> #include <string.h> #define SLENGTH 80 main() { char str[SLENGTH], *eol; int ans; (void)setlocale(LC_ALL, ""); printf("Do you want to perform this operation: "); fgets(str, SLENGTH, stdin); if ((eol = strchr(str, ' ')) != NULL) *eol = ''; /* Replace newline with null */ else return; /* Line entered too long */ ans = rpmatch(str); if (ans == 1) printf("You responded affirmatively "); else if (ans == 0) printf("You responded negatively "); else printf("Your answer did not match "); } RETURN VALUES
A value of 1 is returned if the string value of the response parameter is matched by the affirmative expression; a value of 0 (zero) is returned if the string value of the response parameter is matched by the negative expression. If neither expression matches the string value of the response parameter, a value of -1 is returned. RELATED INFORMATION
Commands: grep(1). Functions: regcomp(3), regexec(3), setlocale(3). Files: locale(4). delim off rpmatch(3)
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