余弦函数近似值.cpp

几个经典的C语言程序

#include<stdio.h>
#include<math.h>
double funcos(double e,double x);
double fact(int x);
int main(void)
{
	double e,x,y;
	printf("Input e:");
	scanf("%lf",&e);
	printf("Input x:");
	scanf("%lf",&x);
	y=funcos(e,x);
	printf("cos%lf=%.2lf\n",x,y);
	return 0;
}
double funcos(double e,double x)
{
	int n,p;
	double z,m;
	z=p=0;
	n=1;
	while(1)
	{
		m=pow(x,p)/fact(p);
		if(m<e)
			break;
		z=z+n*m;
		n=-n;
		p=p+2;
	}
	return z;
}
double fact(int x)
{
	int i;
	double y;
	y=1;
	for(i=1;i<=x;i++)
	{
		y=y*i;
	}
	return y;
}