How I clean the buffer from char signal ?

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C++

#include <stdio.h>

void main()
{
	int num, sum = 0;
	char answer;

	while (1)
	{
		printf_s("add another number ? ");
                //here need to clean the buffeer	
              	scanf_s("%c", &answer);

		if (answer == 'n' || answer == 'N')
			break;
		printf_s("enter the number : ");
		scanf_s("%d", &num);
		sum += num;
	}
	printf_s("Total sum is %d\n", sum);
}

What I have tried:

hey i need to clean the buffer for asking every time the question "add another number? "
and wait to answer.
now the program get the first "y" (yes) and not wait for answer to this question again.
please help

Posted 4-Apr-18 22:13pm

Member 13763735

Updated 4-Apr-18 22:42pm

KarstenK

v2

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KarstenK · Answer 1 · 2018-04-04T22:42:00

The answer is: no, you dont need to clear the variable because the new input is writing it.

But if you want you can do it.

C++

while (1)
{
  printf_s("add another number ? ");
  answer = 0;//clear buffer 
  scanf_s("%c", &answer,1);//added size of the buffer
  //better exit check
  if( (answer != 'y') && (answer =! 'Y') )
	break;

Jochen Arndt · Answer 2 · 2018-04-04T22:44:00

With scanf, the %d format will consume leading white spaces which might be in the input buffer (e.g. the new line not read at the end of a previous input) while the %c format will not do so. But you can make it doing so by inserting a space in front of the format:

C

scanf_s(" %c", &answer);

How I clean the buffer from char signal ?

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