/* Driver for routine gauleg */#include <stdio.h>#include <math.h>#define NRANSI#include "nr.h"#include "nrutil.h"#define NPOINT 10#define X1 0.0#define X2 1.0#define X3 10.0float func(float x){	return x*exp(-x);}int main(void){	int i;	float xx=0.0;	float *x,*w;	x=vector(1,NPOINT);	w=vector(1,NPOINT);	gauleg(X1,X2,x,w,NPOINT);	printf("\n%2s %10s %12s\n","#","x[i]","w[i]");	for (i=1;i<=NPOINT;i++)		printf("%2d %12.6f %12.6f\n",i,x[i],w[i]);	/* Demonstrate the use of gauleg for integration */	gauleg(X1,X3,x,w,NPOINT);	for (i=1;i<=NPOINT;i++)		xx += (w[i]*func(x[i]));	printf("\nIntegral from GAULEG: %12.6f\n",xx);	printf("Actual value: %12.6f\n",		(1.0+X1)*exp(-X1)-(1.0+X3)*exp(-X3));	free_vector(w,1,NPOINT);	free_vector(x,1,NPOINT);	return 0;}#undef NRANSI