#include<bits/stdc++.h>
using namespace std;
int main() {
double a = 10;
cout << log10(a) << endl;//lg
cout << log(a) << endl;//ln
double b = 100;
cout << log(b)/log(a) << endl;//a为底
return 0;
}
输出
1
2.30259
2
#include<bits/stdc++.h>
using namespace std;
int main() {
double a = 10;
cout << log10(a) << endl;//lg
cout << log(a) << endl;//ln
double b = 100;
cout << log(b)/log(a) << endl;//a为底
return 0;
}
输出
1
2.30259
2