6.11.41 erf Function

Calculates the error function of the argument.

Include

<math.h>

Prototype

double erf(double x);

Argument

x

upper limit of summation

Return Value

Returns the error function of the argument, being the summation of the error function from zero to the argument value.

Example

See the notes at the beginning of this chapter or section for information on using printf() or scanf() (and other functions reading and writing the stdin or stdout streams) in the example code.

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

int main(void)
{
  double x, y;

  x = 0.5;
  y = erf(x);
  printf("The summation of the error function from 0 to %f is %f\n", x, y);

  x = -0.75;
  y = erf(x);
  printf("The summation of the error function from 0 to %f is %f\n", x, y);
}

Example Output

The summation of the error function from 0 to 0.500000 is 0.520500
The summation of the error function from 0 to -0.750000 is -0.711156