将十进制数转换为IEEE 单精度二进制浮点数（C代码）

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# `将十进制数转换为IEEE 单精度二进制浮点数（C代码）` #

介绍： IEEE 单精度浮点数分为三个部分

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70]  
**sign**(符号位）**exponent**（8位） **fraction**（尾数 23位） 总共32位

1.  符号(sign)s决定这个数是负数(s=1)还是正数(s=0)
2.  阶码(exponent)E对浮点数加权
3.  尾数(significand) M是一个二进制小数

![在这里插入图片描述][2020012905282878.png]  
但是也有一些特殊的例子：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 1]  
**特殊情况**：当符号位为0(正数)，exponent8位全为0或者符号位为1(负数), exponent8位全为0时，规则发生了一些变化。  
此时，如果为正数，Value=**0.f\*2^(-b+1), b=127**  
如果为负数，Value=**-0.f\*2^(-b+1), b=127**  
例如：int i = 37, float f = \*(float \*)&i(这里是**地址转换**），printf("%f",f).  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 2]

这里正式举一个转换例子：例如将7转成IEEE单精度二进制浮点数  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 3]  
接下来是源代码(可输入任意十进制数，但不能超过电脑最大或最小存储数据)：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 4]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 5]  
运行结果：  
![在这里插入图片描述][20200129053926600.png]  
![在这里插入图片描述][2020012905394621.png]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200129052502258.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA==,size_16,color_FFFFFF,t_70
[2020012905282878.png]: https://img-blog.csdnimg.cn/2020012905282878.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200206032259626.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200206034456240.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20200129053122304.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20200129053842741.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20200129053808934.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzUwMjUzNA==,size_16,color_FFFFFF,t_70
[20200129053926600.png]: https://img-blog.csdnimg.cn/20200129053926600.png
[2020012905394621.png]: https://img-blog.csdnimg.cn/2020012905394621.png