/* Note:Your choice is C IDE */
#include "stdio.h"
#include "math.h"
void main()
{
    float x,X,e,E,s;
    int n,i,I;
    scanf("%f%f",&x,&e);
    n=1;
    i=1;
    I=1;
    s=x;
    X=x;
    do
    {
        n++;
        i+=2;
        I*=i*(i-1);
        X*=x*x;
        E=X/I;
        if(n%2==0)
        s+=-E;
        else
        s+=E;
    }
    while(fabs(E)>=e);
    printf("%f\n",s);
}

I*=i*(i-1);//I越界溢出

        float x,X,e,E,s;
        int  n,i;
        float I;//modify
        

        n=1;
        i=1;
        I=1;
        s=x;
        X=x;
        do
        {
            n++;
            i+=2;
            I/=i*(i-1);//modify
            X*=x*x;
            E=X*I;//modify
            if(n%2==0)
                s+=-E;
            else
                s+=E;
        }
        while(fabs(E)>=e);
        printf("%f\n",s);

太感谢啦！！！