Digital world

這是我的程式範例，主要是參考http://www.cplusplus.com/reference/clibrary/cmath/，如有侵權請通知我

以下就是我的例子，細節可以參考上面的網址，主要在與如何使用這些函數，得到我們想要的數學結果，所以我就不多做解譯了

#include <iostream>
#include <cstdlib>
#include <cmath>

#define PI 3.14159265
using namespace std;

int main(void)
{
    //三角函數，其中cot=1/tan, sec=1/sin, cos=1/csc 
    double param, result;
    int n;
    param = 45.0;
    
    result = sin (param*PI/180);
    printf ("The sine of %1f degrees is %1f. \n", param, result ); 
    
    result = cos (param*PI/180);
    printf ("The cosine of %1f degrees is %1f. \n", param, result ); 
    
    result = tan (param*PI/180);
    printf ("The tangent of %1f degrees is %1f. \n", param, result ); 
    
    param = 0.5;
    result = asin (param) * 180.0 / PI;
    printf ("The arc sin of %1f is %1f degrees\n", param, result);
    
    result = acos (param) * 180.0 / PI;
    printf ("The arc cos of %1f is %1f degrees\n", param, result);
    
    result = atan (param) * 180.0 / PI;
    printf ("The arc tan of %1f is %1f degrees\n", param, result);
    
    //是y/x的atan值，只是會利用正負號去判斷在那一個象限 
    double x, y;
    x = -10.0;
    y = 10.0;
    result = atan2(y,x)*180.0/PI;
    printf ("The arc tan for (x=%1f, y=%1f) is %1f degrees\n", x, y, result);
    
    //雙曲線比較少用到，先跳過
    
    //指數和對數相關
    param=1.0;
    result=exp(param);      //自然指數 
    printf("The exponential value of %1f is %1f. \n", param, result); 


    param=27.0;
    result=frexp(param, &n);    //判斷2的次方數，多少比例 
    printf("%1f * 2^%d = %1f \n", result, n, param);
    
    param=0.9;
    n=5;
    result=ldexp(param, n);
    printf("%f * 2^%d = %f \n", param, n, result);
    
    param=100000;
    result=log(param);      //以e為底 
    printf("ln(%f)=%f \n", param, result);
    
    param=100000;
    result=log10(param);      //以10為底 
    printf("ln(%f)=%f \n", param, result);
    
    param=3.111222;
    double fract_part, int_part;
    fract_part=modf(param, &int_part);  //分割分數的整數和小數部分 
    printf("%1f = %1f + %1f \n", param, int_part, fract_part);
    
    printf("7^3=%1f \n", pow(7,3.0));                   //x的y次方 
    printf("sqrt(49)=%f \n", sqrt(49));                 //開根號 
    printf("ceil of 2.333 is %1f \n", ceil(2.333));        //ceiling and floor
    printf("ceil of -2.333 is %1f \n", ceil(-2.333));
    printf("floor of 2.333 is %1f \n", floor(2.333));
    printf("floor of -2.333 is %1f \n", floor(-2.333));
    printf("The absolute value of 2.333 is %1f \n", fabs(2.333));   //絕對值 
    printf("The absolute value of -2.333 is %1f \n", fabs(-2.333));
    printf("fmod of 7.888/2 is %1f \n", fmod(7.888,2));             //求餘數，可有小數位數 
    
    system("pause");
    return 0;
}