c语言幂函数_了解C / C ++中的幂函数

港控/mmm° 2023-02-28 06:30 222阅读 0赞

c语言幂函数

In this article, we’ll take a look at understanding the power function in C / C++.

在本文中，我们将了解C / C ++中的幂函数。

The power function computes the power of a base, raised to an exponent number.

幂函数计算底数的幂，并提高到指数数。

Let’s look at this function in a bit more detail, using some examples.

让我们使用一些示例来更详细地了解此功能。

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## C / C ++中Power函数的基本语法 **(****Basic Syntax of the Power function in C/C++****)** ##

The `pow()` function takes in a base number and an exponent number, and returns the value `base^(exponent)`.

`pow()`函数接受一个基数和一个指数，并返回值`base^(exponent)` 。

All of these values are of the type `double`.

所有这些值都是`double`类型的。

Also, this function is a part of the `<math.h>` header file, so we must import it first.

另外，此函数是`<math.h>`头文件的一部分，因此我们必须首先将其导入。

#include <math.h>
    
    double pow(double base, double exponent);

In case we give an incorrent range for the input, we will get a `NAN` result.

如果输入的范围不正确，我们将得到`NAN`结果。

For example, if `base` is a negative finite value, and `exponent` is a finite non-integer, we will get a domain error, since the decimal power of a negative number is a complex number, which is not in the scope of C datatypes.

例如，如果`base`是一个负的有限值，而`exponent`是一个有限的非整数，我们将得到一个域错误，因为负数的十进制幂是一个复数，这不在C数据类型的范围内。

Let’s take a look at some examples now.

现在让我们看一些示例。

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## 在C / C ++中使用Power函数–一些示例 **(****Using the Power function in C / C++ – Some Examples****)** ##

Let’s take two integers first, and find the power of them.

让我们先取两个整数，然后求出它们的幂。

#include <stdio.h>
    #include <math.h>
    
    int main() {
        int base = 3;
        int exponent = 5;
    
        int result = (int) pow(base, exponent);
    
        printf("Base = %d, Exponent = %d, Result = %d\n", base, exponent, result);
    
        return 0;
    }

**Output**

**输出量**

Base = 3, Exponent = 5, Result = 242

As you can see, `pow()` did compute `3^5 = 243`.

如您所见， `pow()`确实计算了`3^5 = 243` 。

Let’s check it for floating point numbers now.

现在让我们检查一下浮点数。

#include <stdio.h>
    #include <math.h>
    
    int main() {
        double base = 3.45;
        double exponent = 5.6;
    
        double result = pow(base, exponent);
    
        printf("Base = %.4lf, Exponent = %.4lf, Result = %.4lf\n", base, exponent, result);
    
        return 0;
    }

**Output**

**输出量**

Base = 3.4500, Exponent = 5.6000, Result = 1027.5121

Indeed, it seems to work with floating point exponents and bases as well!

确实，它似乎也适用于浮点指数和基数！

Let’s take another example, which will give us a `NAN` result.

让我们再举一个例子，它将`NAN`结果。

include <stdio.h>
    #include <math.h>
    
    int main() {
        double base = -1;
        double exponent = 5.6;
    
        double result = pow(base, exponent);
    
        printf("Base = %.4lf, Exponent = %.4lf, Result = %.4lf\n", base, exponent, result);
    
        return 0;
    }

**Output**

**输出量**

Base = -1.0000, Exponent = 5.6000, Result = -nan

Here, since `-1^5.6` is a complex number, it will become a `nan` value! So you must be very careful to ensure that your input and output aren’t `nan` values!

在这里，由于`-1^5.6`是复数，因此它将成为`nan`值！ 因此，您必须非常小心以确保您的输入和输出不是`nan`值！

--------------------

## 结论 **(****Conclusion****)** ##

We learned about using `power()` in C / C++, which is useful to compute the mathematical power of a base, to an exponent.

我们学习了在C / C ++中使用`power()` ，该方法对于计算基数的数学功效非常有用。

For similar content, do go through our[ tutorial section][tutorial section] on C programming!

对于类似的内容，请阅读我们有关C编程的[教程部分][tutorial section] ！

## 参考资料 **(****References****)** ##

*  [Linux Manual page][] on the power() function in C
    
    C中power（）函数上的[Linux手册页][Linux Manual page]

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> 翻译自: [https://www.journaldev.com/40777/power-function-in-c-plus-plus][https_www.journaldev.com_40777_power-function-in-c-plus-plus]

c语言幂函数

[tutorial section]: https://www.journaldev.com/c-programming
[Linux Manual page]: https://linux.die.net/man/3/pow
[https_www.journaldev.com_40777_power-function-in-c-plus-plus]: https://www.journaldev.com/40777/power-function-in-c-plus-plus