Floating-point conversions

Real to real or complex to complex
If the types are identical, there is no change. If the types are of a different size, and the value can be represented by the new type, the value is not changed; if the value cannot be represented by the new type, rounding and loss of precision will occur.
Complex to real
The imaginary part of the complex value is discarded. The value of the real part is converted according to the "real to real" rule given above.
Real to complex
The value of the real part is converted according to the "real to real" rule given above. The value of the imaginary part is zero.