在 C 中添加 2 个浮点数

Question

If I have 2 floats and add them together, is the result a float? Or is a double? Or is it compiler defined behavior?

9.0f + 8.0f <--- is the result float, double or compiler defined behavior?

A citation of the correct place in the C specifications would be helpful, if possible.

Answer 1

9.0f + 8.0f 

is the result a float ?

Yes, the type is float .

First, if the corresponding real type of either operand is long double , the other operand is converted, without change of type domain, to a type whose corresponding real type is long double .

Otherwise, if the corresponding real type of either operand is double , the other operand is converted, without change of type domain, to a type whose corresponding real type is double .

Otherwise, if the corresponding real type of either operand is float , the other operand is converted, without change of type domain, to a type whose corresponding real type is float .

C23x dr § 6.3.1.8 1

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Although the type is float , depending on FLT_EVAL_METHOD , the sum may have been calculated using float , double or long double math. This potentially has arithmetic impact on a larger/different valued expression. This part is "compiler implementation defined behavior".