The method of solving power function and exponential function with C language _c language

C Language Pow () function: To find X's y-square (Power)
header file:

#include <math.h>

The POW () function is used to find the Y power of X (the second side), and its prototype is:

  Double pow (double x, double y);

POW () is used to calculate Y-square values with x as the base, and then returns the result. Set the return value to RET, then ret = xy.

Conditions that may cause an error:

• If base x is negative and exponent y is not an integer, it will cause a domain error error.
• If both base x and exponent y are 0, it may or may not be the domain error error, which is related to the library implementation.
• If base x is 0, exponential y is a negative number and may cause domain error or pole error errors, or not;
• If the return value RET is too large or too small, it will cause a range error error.

Error code:

• If a domain error error occurs, the global variable errno is set to EDOM;
• If a pole error or range error error occurs, the global variable errno is set to Erange.

Note that when compiling with GCC, please join-LM.

"Instance" see the code below.

#include <stdio.h>
#include <math.h>
int main ()
{
  printf ("7 ^ 3 =%f\n", pow (7.0, 3.0)); 
   printf ("4.73 ^ =%f\n", pow (4.73, 12.0));
  printf ("32.01 ^ 1.54 =%f\n", pow (32.01, 1.54));
  return 0;
}

Output results:

7 ^ 3 = 343.000000
4.73 ^ a = 125410439.217423
32.01 ^ 1.54 = 208.036691

C language sqrt () function: To find the square root of a given value
header file:

#include <math.h>

sqrt () is used to find the square root of a given value, and its prototype is:

  Double sqrt (double x);

The "parameter" x is the value to compute the square root.

If x < 0, the domain error error is caused and the value of the global variable errno is set to EDOM.

return value returns the X square root.

Note that when compiling with GCC, please join-LM.

The instance calculates the square root of 200. 】

#include <math.h>
Main () {
  double root;
  root = sqrt (m);
  printf ("Answer is%f\n", root);
}

Output results:

Answer is 14.142136