cmath库函数

喜欢ヅ旅行 2023-02-21 14:07 25阅读 0赞

cmath是c++语言中的库函数，其中的c表示函数是来自c标准库的函数，math为数学常用库函数。

cmath中常用库函数：

<table> 
 <thead> 
  <tr> 
   <th>函数</th> 
   <th>作用</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>int abs(int i);</td> 
   <td>返回整型参数i的绝对值</td> 
  </tr> 
  <tr> 
   <td>double fabs(double i);</td> 
   <td>返回浮点数i的绝对值</td> 
  </tr> 
  <tr> 
   <td>round(double x)</td> 
   <td>返回四舍五入值</td> 
  </tr> 
  <tr> 
   <td>double sqrt(double x)</td> 
   <td>返回+√x的值</td> 
  </tr> 
  <tr> 
   <td>double hypot(double x,double y)</td> 
   <td>返回直角三角形斜边的长度(z) <br> z^2=x^2+y^2</td> 
  </tr> 
  <tr> 
   <td>double acos(double x)</td> 
   <td>返回x的反余弦arccos(x)值,x为弧度，<br>1弧度=180/π≈57.3度</td> 
  </tr> 
  <tr> 
   <td>double asin(double x)</td> 
   <td>返回x的反正弦arcsin(x)值,x为弧度，<br>1弧度=180/π≈57.3度</td> 
  </tr> 
  <tr> 
   <td>double atan(double x)</td> 
   <td>返回x的反正切arctan(x)值,x为弧度，<br>1弧度=180/π≈57.3度</td> 
  </tr> 
  <tr> 
   <td>double cos(double x)</td> 
   <td>返回x的余弦cos(x)值,x为弧度，<br>1弧度=180/π≈57.3度</td> 
  </tr> 
  <tr> 
   <td>double sin(double x)</td> 
   <td>返回x的正弦sin(x)值,x为弧度，<br>1弧度=180/π≈57.3度</td> 
  </tr> 
  <tr> 
   <td>double tan(double x)</td> 
   <td>返回x的正切tan(x)值,x为弧度，<br>1弧度=180/π≈57.3度</td> 
  </tr> 
  <tr> 
   <td>double ceil(double x)</td> 
   <td>返回不小于x的最小整数</td> 
  </tr> 
  <tr> 
   <td>double floor(double x)</td> 
   <td>返回不大于x的最大整数</td> 
  </tr> 
  <tr> 
   <td>double fabs(double x);</td> 
   <td>返回双精度参数x的绝对值</td> 
  </tr> 
  <tr> 
   <td>long labs(long n);</td> 
   <td>返回长整型参数n的绝对值</td> 
  </tr> 
  <tr> 
   <td>double exp(double x);</td> 
   <td>返回指数函数e^x的值</td> 
  </tr> 
  <tr> 
   <td>double log(double x);</td> 
   <td>返回logex的值</td> 
  </tr> 
  <tr> 
   <td>double log10(double x)</td> 
   <td>返回log10x的值</td> 
  </tr> 
  <tr> 
   <td>double pow(double x,double y)</td> 
   <td>返回x^y的值</td> 
  </tr> 
  <tr> 
   <td>double pow10(int p)</td> 
   <td>返回10^p的值</td> 
  </tr> 
  <tr> 
   <td>int rand()</td> 
   <td>产生一个随机数并返回这个数</td> 
  </tr> 
  <tr> 
   <td>double atof(char *nptr)</td> 
   <td>将字符串nptr转换成浮点数并返回这个浮点数</td> 
  </tr> 
  <tr> 
   <td>double atol(char *nptr)</td> 
   <td>将字符串nptr转换成长整数并返回这个整数</td> 
  </tr> 
  <tr> 
   <td>double atof(char *nptr)</td> 
   <td>将字符串nptr转换成双精度数,并返回这个数,错误返回0</td> 
  </tr> 
  <tr> 
   <td>int atoi(char *nptr)</td> 
   <td>将字符串nptr转换成整型数, 并返回这个数,错误返回0</td> 
  </tr> 
  <tr> 
   <td>long atol(char *nptr)</td> 
   <td>将字符串nptr转换成长整型数,并返回这个数,错误返回0</td> 
  </tr> 
  <tr> 
   <td>floor(double arg)</td> 
   <td>向下（向0）取整</td> 
  </tr> 
 </tbody> 
</table>

参考链接：  
[https://blog.csdn.net/mary19920410/article/details/63696380][https_blog.csdn.net_mary19920410_article_details_63696380]

[https_blog.csdn.net_mary19920410_article_details_63696380]: https://blog.csdn.net/mary19920410/article/details/63696380