pks38rqfp/main.cpp

#include <iostream>
#include<stdio.h>
#include<math.h>
#define pi 3.14
using namespace std;
const double e = 2.718281828459;

int san()
{
	int a;
	double b;
	printf("请输入你要计算的角度b:");
    scanf("%d",&a);
    b=a*pi/180;
	printf("sin(b)=%f\n",sin(b)) ;
	printf("cos(b)=%f\n",cos(b)) ;
	printf("tan(b)=%f\n",tan(b)) ;
	return 0;

 } 
 
int exp()
{
int x;
double y;
printf("please input x:");
scanf("%d", &x);
if (x > 0)
{
y = exp(x);
}
else if (x< 0)
{
y = exp(x);
}
else
{
printf("y==1\n");
}
printf("y=%f\n", y);
}

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 log2()
{
	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"。
	return 0;
}

int add()
{
	
int a,b,d;
char c;
printf("输入运算式：");
scanf("%d%c%d",&a,&c,&b);
switch(c)
{
case'+':d=a+b;break;
case'-':d=a-b;break;
case'*':d=a*b;break;
case'/':d=a/b;break;
}
printf("%d%c%d=%d\n",a,c,b,d);
}


int main()
{
	san(); 
	exp(); 
	log2();
	add();
   return 0;
}