How to clear input buffer in C?

Question

I have the following program:

int main(int argc, char *argv[])
{
  char ch1, ch2;
  printf(\"Input the first character:\"); // Line 1
  scanf(\"%c\", &ch         


        

Answer 1

Short, portable and declared in stdio.h

stdin = freopen(NULL,"r",stdin);

Doesn't get hung in an infinite loop when there is nothing on stdin to flush like the following well know line:

while ((c = getchar()) != '\n' && c != EOF) { }

A little expensive so don't use it in a program that needs to repeatedly clear the buffer.

Stole from a coworker :)