Methods to find exponential function and exponential function in C language

C language pow() function: find x to the power of y (power)
Header file:

#include <>

The pow() function is used to find the y power (to the power) of x, and its prototype is:

  double pow(double x, double y);

pow() is used to calculate the y power value with x and then return the result. Suppose the return value is ret, then ret = xy.

Situations that may lead to errors:

• If the base x is negative and the exponent y is not an integer, a domain error error will be caused.
• If the base x and the exponent y are both 0, it may cause a domain error error or may not; this is related to the implementation of the library.
• If the base x is 0 and the exponent y is negative, it may cause domain error or pole error error, or it may not be; this is related to the implementation of the library.
• 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 will be set to EDOM;
• If a pole error or range error error occurs, the global variable errno will be set to ERANGE.

Note that when compiling using GCC, please add -lm.

[Example] Please see the code below.

#include <>
#include <>
int main ()
{
  printf ("7 ^ 3 = %f\n", pow (7.0, 3.0) );
  printf ("4.73 ^ 12 = %f\n", pow (4.73, 12.0) );
  printf ("32.01 ^ 1.54 = %f\n", pow (32.01, 1.54) );
  return 0;
}

Output result:

7 ^ 3 = 343.000000
4.73 ^ 12 = 125410439.217423
32.01 ^ 1.54 = 208.036691

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

#include <>

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

  double sqrt(double x);

[Parameter] x is the value to calculate the square root.

If x < 0, it will cause a domain error error and set the value of the global variable errno to EDOM.

【Return value】Returns x square root.

Note that when compiling using GCC, please add -lm.

[The example calculates the square root value of 200. 】

#include <>
main(){
  double root;
  root = sqrt(200);
  printf("answer is %f\n", root);
}

Output result:

answer is 14.142136