请大佬指导，计算题

#include <stdio.h>
#include <math.h>

double funcos( double e, double x );

int main()
{   
    double e, x;

    scanf("%lf %lf", &e, &x);
    printf("cos(%.2f) = %.6f\n", x, funcos(e, x));
   
    return 0;
}

double funcos( double e, double x )
{
    int numerator,denominator,flag,i;
    double item,sum;
    i=1;
    flag=-1.0;
    denominator=2;
    numerator=x*x;
    sum=0;
    do
    {
        item=flag*numerator/denominator;
        sum=sum+item;
        numerator=numerator*x*x;
        denominator=denominator*(denominator+1)*(denominator+2);
        flag=-flag;
    }while(fabs(item)>=e);
    return sum;
}//输入0.01 -3.14 为什么得不到-0.999899