3-8.c

一些简单的c51程序

#include <REG52.H>              
#include <stdio.h>                
#include <math.h>
void main (void) {

	double pi,t;
	long int n,s;
t=1.0;
	n=1;
	s=1;
	pi=0.0;

	SCON = 0x50; 
TMOD |= 0x20; 
TH1 = 0xf3; 
TR1 = 1;
TI = 1; 
	while(fabs(t)>=1e-6)
	{
		pi=pi+t;
		n=n+2;
		s=-s;
		t=(float)(s)/(float)(n);
	}
	pi=pi*4.0; 
	printf("pi=%lf\n",pi);
    while (1) {};
}