编写程序：计算π的近似值，π的计算公式为
#include<stdio.h>
main()
{ int n,i; double t,
sum;/*1*/
printf("请输入n的值\n");
scanf("%d",&n);
sum=2; i=1; t=2;/*2*/
while(i<n) { t=t*(2*i)*(2*i)/(2*i-1)/(2*i+1);
/*3*/ // sum=sum*t; i=i+1; }
printf("π的值=%f\n",t);/*4*/ }
或。
写一个Java程序来实现蒙特卡洛法求π的近似值：
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class MonteCarloPi {
public static void main(String[] args) throws Exception{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.print("How many darts shoud I toss at the board?\n");
String s = br.readLine();
int numberOfDarts = Integer.parseInt(s.trim());
double radius = 1.0;
Dartboard d = new Dartboard(radius);
for(int i=1; i<=numberOfDarts; i++){
Toss t = Toss.getRandom(radius);
d.strike(t);
}
double fractionIn = d.getFractionIn();
double pi = 4.0 * fractionIn;
System.out.println("Pi is approximately "+pi);
}
}
class Dartboard{
private double radius;
private int insideCircle, outsideCircle;
public Dartboard(double radius){
this.radius = radius;
insideCircle = 0;
outsideCircle = 0;
}
public void strike(Toss toss){
double x = toss.getX();
double y = toss.getY();
if(Math.sqrt(x*x + y*y) < radius)
insideCircle++;
else
outsideCircle++;
}
public double getFractionIn() {
double total = (double) (insideCircle + outsideCircle);
return (double) insideCircle/total;
}
}
class Toss{
private double x,y;
public Toss(double x, double y){
this.x = x;
this.y = y;
}
public double getX(){return x;}
public double getY(){return y;}
public static Toss getRandom(double radius){
double x,y;
double size = Math.random();
double sign = Math.random();
size = size * radius;
if(sign > 0.5)
x = size;
else
x = -size;
size = Math.random();
sign = Math.random();
size = size * radius;
if(sign > 0.5)
y = size;
else
y = -size;
return new Toss(x,y);
}
}
扩展资料：
C语言:用循环结构分别编写程序
#include
void main()
{
\x09int n=1;
\x09float temp;
\x09float sum=0;
\x09do
\x09{
\x09\x09temp=(float)1/(2*n-1);
\x09\x09if(n%2==1)
\x09\x09\x09sum+=temp;
\x09\x09else
\x09\x09\x09sum-=temp;
\x09\x09n++;
\x09}while(temp>=0.000001);
\x09printf("Pi=%f\n",sum*4);
}
{
int n,i;
float sum;
printf("请输入n的值\n");
scanf("%d",&n);
sum=2;
i=1;
while(i<n)
{ // 你的t是没有用的，而且你用了int肯定完蛋了，另外注意除法!!!
sum=sum*(2*i)*(2*i)/(2*i-1)/(2*i+1); i=i+1;
}
printf("π的值=%f\n",sum);
}
