【每日刷题】 PAT 基础习题集 7-15 计算圆周率 （15 分)

题目描述：

代码如下：

//7-15
#include <stdio.h>
#include <math.h>
double fact( int n );
int main ( void )
{
	double e;
	scanf( "%lf", &e );
	int i = 1;
	double temp = 1, fz, fm = 1, sum = 0, t = 1;
	while( temp >= e ){
		sum += temp;
		fz = fact( i++ );
		fm = fm * ( t + 2 );
		temp = fz / fm;
		t += 2;
	}
	sum += temp;
	printf( "%lf", sum * 2 );
	return 0;
}
double fact( int n )
{
	double ret = 1;
	for( int i = 1; i <= n; i++ )
		ret *= i;
	return ret;
}