tst_ungetchar.c

这是《Keil Cx51 V7.0单片机高级语言编程与uVision2应用实践》教材各章中列出的全部程序例子。

#include <stdio.h>
void tst_ungetchar (void) {
   char k;
   while (isdigit (k = getchar ())) {
          /* stay in the loop as long as k is a digit */
   }
   ungetchar (k);
 }