C language: C language used to clear the input buffer in the case of standard input (stdin)

C language: C language used to clear the input buffer in the case of standard input (stdin)
C language clearing input buffer in the standard input (stdin) case of use 1:

// Function: enter a number, a character, and 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 ;}

 

Result: 7 hello bit. Press any key to continue... analysis: If no character is entered, the "hello bit" is output directly, because when you press enter ('\ n'), it is equivalent to inputting a character, then we need to clear the buffer handler 2:

# Include <stdio. h> int main () {int num = 0; char ch = ''; scanf (" % d ", & num);/* fflush (stdin ); * /// errors are prone to errors when clearing the buffer. It is not recommended to use/* scanf ("% * [^ \ n]"); * // It is not easy to use, easy to invalidate setbuf (stdin, NULL); // converts the stdin input stream from the default buffer to a buffer-free zone. scanf ("% c", & ch) can be used ); printf ("hello bit \ n"); system ("pause"); return 0 ;}

 

Result: 5. Press any key to continue jhello bit... program 3:

// Function: enter a number, a character, and 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 ;}

 

Result: 8. Press any key to continue shello bit... analysis: It is recommended that program 3 Use getchar () to obtain the buffer characters until the obtained C is "\ n" or the file Terminator EOF, this method perfectly clears the input buffer and is portable.