您是否嘗試過比較IL(例如,與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; }
所有這三個成爲(給予或自己取的名字):
.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
}
因此,沒有:有確切零差價。