Routine Name: relativeError

Author: Christopher Johnson

Language: C++. Tested with g++ compiler.

Declared in: “error.h”

Description/Purpose: calculates relative error of an approximation of value x_bar by x.

Input: Exact value x_bar and approximation x - both double type.

Output: Return the relative error of the approximation as a double type

Usage/Example:

#include <iostream>
#include "error.h"

int main (void)
{
	const double PI=3.141592653589793238462643;
	double x = 3.14; 
	std::cout << "Relative error in a 3 digit approximation of PI is " << absoluteError(PI,x) << "\n";
}

Output from the lines above:

Relative error in a 3 digit approximation of PI is 0.000507215

Implementation/Code: The following is the code for relativeError(xbar, x)

double relativeError(double xbar, double x)
{
	return std::abs(xbar-x)/xbar;
}

Last Modified: Jan/2018