C++ pow函数实现 ~~晚间划水

用泰勒展开实现pow函数，实际效果还不如直接循环

但是这对于初步理解泰勒展开还是有一点帮助的

#include<iostream>
#include<cmath>
using namespace std;

double exp_x(double x){
    double p=x,ans=1;
    for(int i=1;i<=10000;++i){
        ans+=p;
        p=p*x/(i+1);
    }
    return ans;
}

double log_e(double x){
    if(x<=0){
        puts("Error");
        exit(0);
    }
    double ans=0;
    while(x>=1){
        ans=ans+1;
        x/=exp_x(1);
    }
    double p=x-1,sgn=1;
    for(int i=1;i<=10000;++i){
        ans+=sgn*p/i;
        p=p*(x-1);
        sgn=-sgn;
    }
    return ans;
}

double power(double x,double y){return exp_x(log_e(x)*y);}

int main(){
    double x,y;
    while(cin>>x>>y&&(x||y)){
        cerr<<power(x,y)<<endl;
        cerr<<pow(x,y)<<endl;
    }
    system("pause");
    return 0;
}