3-2.c

一些简单的c51程序

#include <REG52.H>              
#include <stdio.h>                

void main (void) 
{
	float x,y;
	SCON = 0x50; 
TMOD |= 0x20; 
TH1 = 0xf3; 
TR1 = 1;
TI = 1;
	printf("input x,y:");
	scanf("%f",&x ) ;
	if (x>=0)
		if (x>0)
			y=1;
		else
			y=0;
	else
		y=-1;
	printf("y=%4.0f\n",y);
    while (1) {};
}