package Hello;
import java.io.*;
import java.util.*;
import java.math.*;
public class Hello{
	
	public static double mypow(double e,double x) {
		double ans=Math.pow(e, x);
		return ans;
	}
	
	public static double mylog(double a,double x) {
		double ans=Math.log(x)/Math.log(a);
		return ans;
	}
	
	public static double myadd(double a,double b) {
		return a+b;
	}
	
	public static double mysub(double a,double b) {
		return a-b;
	}
	
	public static double mymultiply(double a,double b) {
		return a*b;
	}
	
	public  static double mydivide(double a,double b) {
		return a/b;
	}
	
	public static double mysin(double x) {
		return Math.sin(x);
	}
	
	public static double mycos(double x) {
		return Math.cos(x);
	}
	
	public  static double mytan(double x) {
		return Math.tan(x);
	}
	
	public static void main(String args[]) {
		Scanner cin=new Scanner(System.in);
		System.out.printf("功能表：\n说明：输入add a b执行a+b\n"
				+ "pow e x\nlog a x\nadd a b\nsub a b\nmultiply a b\n"
				+ "divide a b\nsin x\ncos x\ntan x\nquit:退出\n");
		while (cin.hasNext()) {
			String op=cin.next();
			double a,b,ans=0;
			switch(op) {
				case "pow":
					a=cin.nextDouble();
					b=cin.nextDouble();
					ans=mypow(a,b);
					break;
				case "log":
					a=cin.nextDouble();
					b=cin.nextDouble();
					ans=mylog(a,b);
					break;
				case "add":
					a=cin.nextDouble();
					b=cin.nextDouble();
					ans=myadd(a,b);
					break;
				case "sub":
					a=cin.nextDouble();
					b=cin.nextDouble();
					ans=mysub(a,b);
					break;
				case "multiply":
					a=cin.nextDouble();
					b=cin.nextDouble();
					ans=mymultiply(a,b);
					break;
				case "divide":
					a=cin.nextDouble();
					b=cin.nextDouble();
					while(b==0) {
						System.out.printf("除数不能为0，请重新输入除数!\n");
						b=cin.nextDouble();
					}
					ans=mydivide(a,b);
					break;
				case "sin":
					a=cin.nextDouble();
					ans=mysin(a);
					break;
				case "cos":
					a=cin.nextDouble();
					ans=mycos(a);
					break;
				case "tan":
					a=cin.nextDouble();
					ans=mytan(a);
					break;
				default:
					System.out.println("已退出计算器\n");
					return;
			}
			System.out.printf("%f\n",ans);
		}
		cin.close();
	}
}