📜  C++ atan()

📅  最后修改于: 2020-09-25 07:22:57             🧑  作者: Mango

C++中的atan() 函数以弧度形式返回数字(参数)的反正切值。

此函数在头文件中定义。

[Mathematics] tan-1x = atan(x) [In C++ Programming];

atan()原型[从C++ 11标准开始]

double atan(double x);
float atan(float x);
long double atan(long double x);
double atan (T x); // For integral type

atan()参数

atan() 函数采用单个强制性参数(可以为正,负或零)

atan()返回值

atan() 函数返回[-π/ 2,π/ 2]范围内的值。

示例1:atan()如何工作?

#include 
#include 

using namespace std;

int main()
{
  double x = 57.74, result;
  result = atan(x);
  
  cout << "atan(x) = " << result << " radians" << endl;
  
  // Output in degrees
  cout << "atan(x) = " << result*180/3.1415 << " degrees" << endl;
  
  return 0;
}

运行该程序时,输出为:

atan(x) = 1.55348 radians
atan(x) = 89.0104 degrees

示例2:具有整数类型的atan() 函数

#include 
#include 
#define PI 3.141592654

using namespace std;

int main()
{
  int x = 14;
  double result;
  
  result = atan(x);
  
  cout << "atan(x) = " << result << " radians" << endl;
  // Output in degrees
  cout << "atan(x) = " << result*180/3.1415 << " degrees" << endl;
  
  return 0;
}

运行该程序时,输出为:

atan(x) = 1.49949 radians
atan(x) = 85.9169 degrees