C++ acos()用法及代码示例

acos()是C++ STL中的内置函数，该函数返回弧度数(参数)的反余弦值。 acos()函数返回的值始终位于– $\pi$ 到+ $\pi$

用法:

acos(data_type x)

参数：此函数接受一个强制性参数x，该参数指定应计算其反余弦值的值。它必须介于-1和+1之间，否则将抛出域错误(范围错误)。该参数可以是double，float或long double数据类型。

返回：该函数返回介于– $\pi$ 和+ $\pi$ 。逆时针角度以弧度为单位。

示例1:

// C++ program to demonstrate 
// the acos() function 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double x = 1.0; 
  
    // Function call to calculate acos(x) value 
    double result = acos(x); 
  
    cout << "acos(1.0) = " << result << " radians" << endl; 
    cout << "acos(1.0) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

输出：

acos(1.0) = 0 radians
acos(1.0) = 0 degrees

示例2:

// C++ program to demonstrate 
// the acos() function 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double result; 
    int x = -1; 
  
    // Function call to calculate acos(x) value 
    result = acos(x); 
  
    cout << "acos(-1) = " << result 
         << " radians" << endl; 
    cout << "acos(-1) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

输出：

acos(-1) = 3.14159 radians
acos(-1) = 180 degrees

错误和异常：

当字符串或字符作为参数传递时，该函数不返回任何匹配函数来调用错误。
当传递超出范围的数字作为参数时，该函数将返回nan。

以下示例程序旨在说明上述方法的错误和异常：

示例3:

// C++ program to demonstrate the acos() 
// function errors and exceptions 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double result; 
    string x = "gfg"; 
    result = acos(x); 
  
    cout << "acos(x) = " << result 
         << " radians" << endl; 
    cout << "acos(x) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

输出：

prog.cpp:10:17: error: no matching function for call to 'acos(std::__cxx11::string&)'
  result = acos(x);

示例4:

// C++ program to demonstrate the 
// acos() function errors and exceptions 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    double x = 3.7, result; 
  
    // Function call to calculate acos(x) value 
    result = acos(x); 
  
    cout << "acos(3.7) = " << result 
         << " radians" << endl; 
    cout << "acos(3.7) = " << result * 180 / 3.141592 
         << " degrees" << endl; 
  
    return 0; 
}

输出：

acos(3.7) = nan radians
acos(3.7) = nan degrees

相关用法

注：本文由纯净天空筛选整理自pawan_asipu大神的英文原创作品 acos() function in C++ STL。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。