c语言幂函数_了解C / C ++中的幂函数-白红宇

c语言幂函数_了解C / C ++中的幂函数

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发布时间：2019-05-11

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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。

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 
    
     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。

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 
    
     #include 
     
      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 
    
     #include 
     
      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 
    
     #include 
     
      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！