C++ — type of the division?

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陌清茗
陌清茗 2021-02-20 02:05

I want to make sure that my understanding of the return type of C++ division,

int / int => return is int?

float / float => return is which type? float?

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  •  滥情空心
    2021-02-20 02:58

    All of those are correct. Here's what the C++03 standard says (§5/9):

    Many binary operators that expect operands of arithmetic or enumeration type cause conversions and yield result types in a similar way. The purpose is to yield a common type, which is also the type of the result. This pattern is called the usual arithmetic conversions, which are defined as follows:

    • If either operand is of type long double, the other shall be converted to long double.
    • Otherwise, if either operand is double, the other shall be converted to double.
    • Otherwise, if either operand is float, the other shall be converted to float.
    • Otherwise, the integral promotions (4.5) shall be performed on both operands.
    • Then, if either operand is unsigned long the other shall be converted to unsigned long.
    • Otherwise, if one operand is a long int and the other unsigned int, then if a long int can represent all the values of an unsigned int, the unsigned int shall be converted to a long int; otherwise both operands shall be converted to unsigned long int.
    • Otherwise, if either operand is long, the other shall be converted to long.
    • Otherwise, if either operand is unsigned, the other shall be converted to unsigned.

    [Note: otherwise, the only remaining case is that both operands are int]

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