Non-uniform distributed random numbers

gistfile1.c

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

const unsigned int N = 100;
const double MIN = 1;
const double MAX = 10;
const double EXPONENT = 2;

double f(double x) {
	if (EXPONENT == -1) {
		return exp(log(MAX-MIN)*x)*MIN;
	} else {
		return exp(log(x*(-pow(MIN,EXPONENT+1)+pow(MAX,EXPONENT+1))+pow(MIN,EXPONENT+1))/(EXPONENT+1));
	}
}

int main(int argc, char** argv) {
	// provide initial random seed
	srand(time(NULL));

	printf("# i\tuniform\tnon-uniform\n");
	for (unsigned int i = 0; i < N; ++i) {
		double x = drand48();

		printf("%i\t%.18lg\t%.18lg\n", i, x, f(x));
	}

	exit(EXIT_FAILURE);
}