如何将一个float变量赋给一个unsigned int变量，位图，而不是转换 [英] How can I assign a float variable to an unsigned int variable, bit image, not cast

问题描述

我知道这是一个奇怪的事情，它不可移植。但我有一个分配的unsigned int数组，偶尔我想存储一个浮点数。我不想转换float或将其转换为最接近的等价int;我想把浮点的精确位图存储在unsigned int的分配空间中，这样我可以稍后将它作为一个浮点检索，并保留其原来的浮点值。

解决方案

这可以通过一个简单的副本实现：

  uint32_t dst; 
 float src = get_float（）; 
 
 char * const p = reinterpret_cast< char *>（& dst）; 
 
 std :: copy（p，p + sizeof（float），reinterpret_cast< char *>（& src））; 
 
 //现在读取dst 
  

>

I know this is a bizarre thing to do, and it's not portable. But I have an allocated array of unsigned ints, and I occasionaly want to "store" a float in it. I don't want to cast the float or convert it to the closest equivalent int; I want to store the exact bit image of the float in the allocated space of the unsigned int, such that I could later retrieve it as a float and it would retain its original float value.

解决方案

This can be achieved through a simple copy:

uint32_t dst;
float    src = get_float();

char * const p = reinterpret_cast<char*>(&dst);

std::copy(p, p + sizeof(float), reinterpret_cast<char *>(&src));

// now read dst

Copying backwards works similarly.

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