ios - How can I convert from degrees to radians? -

i trying convert obj-c code swift code don't know equivalent of code should ?

#define degrees_to_radians(degrees)((m_pi * degrees)/180) 

i googled , found this

but don't understand how convert in swift in case?

xcode 9 • swift 4

extension binaryinteger {     var degreestoradians: cgfloat { return cgfloat(int(self)) * .pi / 180 } }  extension floatingpoint {     var degreestoradians: self { return self * .pi / 180 }     var radianstodegrees: self { return self * 180 / .pi } } 

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playground

45.degreestoradians         // 0.785398163397448  int(45).degreestoradians    // 0.785398163397448 int8(45).degreestoradians   // 0.785398163397448 int16(45).degreestoradians  // 0.785398163397448 int32(45).degreestoradians  // 0.785398163397448 int64(45).degreestoradians  // 0.785398163397448  uint(45).degreestoradians   // 0.785398163397448 uint8(45).degreestoradians  // 0.785398163397448 uint16(45).degreestoradians // 0.785398163397448 uint32(45).degreestoradians // 0.785398163397448 uint64(45).degreestoradians // 0.785398163397448  double(45).degreestoradians    // 0.7853981633974483 cgfloat(45).degreestoradians   // 0.785398163397448 float(45).degreestoradians     // 0.7853981 float80(45).degreestoradians   // 0.785398163397448278999