[C language] simulation implementation of pow function (recursion)

One 、 Library function ——pow Function function introduction and use demonstration

1.API Explanation in the document

（1） function ：Calculates x raised to the power of y. Computation x Of y Power

（2） Parameters ： base:Base value. Cardinality

​ exponent:Exponent value. The index

（3） Return value ：pow returns the value of xy. No error message is printed
on overflow or underflow namely Pow return xy Value . No error message will be printed when overflow or underflow .

（4） The header file ：<math.h>

（5） Compatibility ：ANSI, Win 95, Win NT

（6） Abstract ：The pow function computes x raised to the power of y.
namely pow Function calculation x Of y Power

pow does not recognize integral floating-point values greater than 264, such as 1.0E100. namely pow Cannot identify greater than 264 Integer floating point value of , for example 1.0E100.

2.pow Function use demonstration

#include <math.h>
#include <stdio.h>

int main()
{
    
   double x = 2.0, y = 3.0, z;
   z = pow( x, y );
   printf( "%.1f to the power of %.1f is %.1f\n", x,y,z);
   return 0;
}

Two 、pow Simulation Implementation of function

Realize the idea ：

#include <stdio.h>
double Pow(int n,int k)
{
    
	if (k > 0)
		return n * Pow(n, k - 1);
	else if (k == 0)
		return 1;
	else
		return 1.0 / Pow(n, -k);
}
int main()
{
    
	int n ,k;
	scanf("%d%d", &n,&k);
	double ret = Pow(n, k);
	printf("%.2lf\n",ret);
	return 0;
}

3、 ... and 、 Add

1.API What is the document ？

In short, it is For all API A clear explanation of the call and the parameters involved .. To be specific , It's every one API What can be done , And right API
Explanation of each parameter in , Including their types 、 Format 、 Possible values 、 Validation rule 、 Whether it is necessary, etc .

Reference resources : https://zhuanlan.zhihu.com/p/36729484#:~:text=API

2. Suggestions for naming custom functions in simulation implementation

Distinguish between upper and lower case letters , It's best not to conflict with the naming of library functions .