Question

Consider the following signature in C#:

double Divide(int numerator, int denominator); 

Is there a performance difference between the following implementations?

return (double)numerator / denominator;  return numerator / (double)denominator;  return (double)numerator / (double)denominator; 

I’m assuming that both of the above return the same answer.

Have I missed any other equivalent solution?

Answer 1

Have you tried comparing the IL (for example, with Reflector)?

static double A(int numerator, int denominator) { return (double)numerator / denominator; }  static double B(int numerator, int denominator) { return numerator / (double)denominator; }  static double C(int numerator, int denominator) { return (double)numerator / (double)denominator; } 

All three become (give or take the name):

.method private hidebysig static float64 A(int32 numerator, int32 denominator) cil managed {     .maxstack 8     L_0000: ldarg.0 // pushes numerator onto the stack     L_0001: conv.r8 // converts the value at the top of the stack to double     L_0002: ldarg.1 // pushes denominator onto the stack     L_0003: conv.r8 // converts the value at the top of the stack to double     L_0004: div     // pops two values, divides, and pushes the result     L_0005: ret     // pops the value from the top of the stack as the return value } 

So no: there is exactly zero difference.