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为什么C和C ++在算术操作期间会促进`short''Int'?

发布于2025-03-12
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Why Do C and C   Promote `short` to `int` During Arithmetic Operations?
为什么在C和C?

Integer Promotions

的背景在C中,Integer促销是在表达式中自动转换的,以确定数据类型在表达式中自动转换。适用于算术表达式的通常的算术转换涉及将其促进到INT,如果它可以代表所有简短值。 Otherwise, it is promoted to unsigned int.

Rationale for Wider Calculations

According to the C standard rationale, allowing calculations in wider types than necessary was introduced to:

Generate smaller and faster code

Provide more accurate results

This design decision is attributed to the varying hardware architectures at the time, where using wider types could result in more efficient code execution.

Implications for Short Operands
  • When a short operand is encountered in an arithmetic operation, it undergoes integer promotions.此促销通常会将其转换为INT,它提供了更大的值范围,并确保操作的一致数据类型。
  • 考虑以下代码spippet:
  • 在这里,s和t是简短的类型。但是,它们添加的结果存储在X中,该X具有INT类型。这与C标准中定义的通常的算术转换和整数促销相一致。
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