This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.
#include <iostream>
using namespace std;
const double e = 2.718281828459;
double log(double x)
{
long t = 0;
while (x > 1)
{
x /= e;
++t;
}
x = x - 1;
double ret = 0;
int k = 1;
double temp;
double c = 1;
double xx = 1;
while (1)
{
xx *= x;
temp = c * xx / k;
c *= -1;
ret += temp;
++k;
if (temp > -0.00000001)
break;
}
return ret + t;
}
int main()
{
double a, x; // 计算log(a,x);
// 用ln(x)/ln(a)计算。
cin >> a >> x;
if (a <= 0 || x <= 0 || a == 1)
{
cout << "输入不正确！" << endl;
}
double ans = log(x) / log(a);
cout << ans << endl; // log(x)返回x的自然对数，使用虚include"cmath"或"math.h"。
