csample1.c

c51学习的好书！

 #include <reg51.h>                        
 #include <stdio.h>                          
 /* 外部函数说明 */
 extern int getnumber();
 extern output(int);
 main () {
   int number1, number2;
   bit operation;                             
 /* 初始化8051串行口 */
   SCON = 0x52;    
   TMOD = 0x20;    
   TCON = 0x69;    
   TH1 =  0xf3;    
   printf ("\n\n C51 Compiler demonstration program\n\n");
   while (1)     {
     number1 = getnumber ();                    
     number2 = getnumber ();                    
     printf ("Input operation: '+' (ADD) or '-' (SUB) ? ");
     operation = (getchar () == '+');          
     output (operation ? (number1 + number2) : (number1 - number2) );
   }
 }