C++正弦/餘弦計算器

Question

沒有關注餘弦定律，我的代碼波紋管試圖解決給定的邊和角度。如果還有一種方法，我如何使用cin >>來檢索多個字符，如您所見，我要求用戶輸入'A'或'S'。

Here is my code and the results

#include <iostream> 
#include <math.h> 
using namespace std; 
int main() 
{ 
    char solvefor; 
    double A; // I used doubles to have specific answers 
    double a; 
    double B; 
    double b; 
    double C; 
    double c; 

    cout << "What are you trying to solve? <ASA(A) or SSA(S)>"; 
    cin >> solvefor; 
    if (solvefor == 'S') 
    { 
     cout << "What is the value of b?" << endl; 
     cin >> b; 
     cout << "What is the angle B?" << endl; 
     cin >> B; 
     cout << "What is the side c?" << endl; 
     cin >> c; 
     C = asin((sin(B)/b) * c); 
     cout << "Your missing C angle is " << C << endl; 
     A = 180 - C - B; 
     cout << "Your missing A angle is " << A << endl; 
     a = (sin(A) *b)/sin(B); 
    } else { 
     return 0;  //I will work on law of cosine later 
    } 
} 

我會收到弧度而不是度的答案，任何幫助嗎？

Answer 1

如何從價值角度轉換成弧度

#define PI 3.14159265 
C_in_radian = C * (PI/180.0); // here C is in degree 

修改代碼如下。

C = asin((sin(B)/b) * c); 
double C_raidan = C * (PI/180.0); 
cout << "Your missing C angle is " << C_raidan << endl; 
A = 180 - C - B; 
double A_radian = A * (PI/180.0); 
cout << "Your missing A angle is " << A_radian << endl; 

輸出：

What are you trying to solve? <ASA(A) or SSA(S)> S 
What is the value of b? 
8 
What is the angle B? 
31 
What is the side c? 
13 
Your missing C angle is -0.0125009 
Your missing A angle is 2.61304 

請通過本 - Converting Radians to Degrees and vice-versa。

如果您想知道如何使用C++編寫asin或sin，請參閱asin和sin。

編輯

據@ G.Sliepen建議，我們應該用M_PI從<cmath>或<math.h>。

我們只需要使用：

#define _USE_MATH_DEFINES // for C++ 
#include <cmath> 

OR

#define _USE_MATH_DEFINES // for C 
#include <math.h> 

然後我們可以使用：

double C_raidan = C * (M_PI/180.0); // M_PI is a math constant 

見reference。