C: C language emptying input buffers for use in standard input (stdin) cases

the C language empties the input buffer use in standard input (stdin) Cases

Program 1:

Function: First enter a number, then enter a character, output hello bit

#include <stdio.h>

int Main ()

{

int num = 0;

Char ch = "' ;

scanf ("%d", &num);

scanf ("%c", &ch);

printf ("Hello bit\n");

System ("pause");

return 0;

}

Results:

7

Hello bit

Please press any key to continue ...

Analysis: There is no input character, the output is directly " Hello bit "Because when you click Enter ('\ n'), it is equivalent to entering a character, then we need to clear the buffer processing

Program 2:

#include <stdio.h>

int Main ()

{

int num = 0;

Char ch = "' ;

scanf ("%d", &num);

/*fflush (stdin); * * //Empty buffer error prone, not recommended

/*SCANF ("%*[^\n]"); *///is not good, easy to fail

setbuf (stdin, NULL); //enable the stdin input stream to be converted from the default buffer to no buffer

scanf ("%c", &ch);

printf ("Hello bit\n");

System ("pause");

return 0;

}

Results:

5

J

Hello bit

Please press any key to continue ...

Program 3:

Function: First enter a number, then enter a character, output hello bit

#include <stdio.h>

#define clear_buf() \

int          c = 0; \

while ((c = GetChar ())! = EOF && c! = ' \ n ') \

{    \

   ; \

}

int Main ()

{

int num = 0;

Char ch = "' ;

scanf ("%d", &num);

Clear_buf ();

scanf ("%c", &ch);

printf ("Hello bit\n");

System ("pause");

return 0;

}

Results:

8

S

Hello bit

Please press any key to continue ...

Analysis: Program 3 recommended to use, keep using GetChar () gets the characters in the buffer until the obtained C is "\ n" or the end of file is EOF, this method perfectly clears the input buffer and is portable

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C: C language emptying input buffers for use in standard input (stdin) cases