how to calculate inverse trigonometric values in c 2b 2b

1
2 * C++ Program to Obtain Inverse of a Trigonometric Ratio
3 */
4#include <iostream>
5#include <cmath>
6#include <iomanip>
7 
8int main()
9{
10    double value, result;
11    int choice;
12 
13    std::cout << "Enter a choice " << std::endl;
14    std::cout << "1. Inverse Sine" << std::endl;
15    std::cout << "2. Inverse Cosine" << std::endl;
16    std::cout << "3. Inverse Tangent" << std::endl;
17    std::cin  >> choice;
18    switch (choice) {
19        case 1:
20            std::cout << "Enter a value ";
21            std::cin  >> value;
22            std::cout << "asin(val) = " << std::setprecision(3)
23                      << asin(value) << std::endl;
24            break;
25        case 2:
26            std::cout << "Enter a value ";
27            std::cin  >> value;
28            std::cout << "acos(val) = " << std::setprecision(3)
29                      << acos(value) << std::endl;
30            break;
31        case 3:
32            std::cout << "Enter a value ";
33            std::cin  >> value;
34            std::cout << "atan(val) = " << std::setprecision(3)
35                      << atan(value)  << std::endl;
36            break;
37    }
38    return 0;
39}