/* Driver for routine expint */#include <stdio.h>#include <stdlib.h>#include <string.h>#define NRANSI#include "nr.h"#include "nrutil.h"#define MAXSTR 80int main(void){	char txt[MAXSTR];	int i,nval,n;	float val,x;	FILE *fp;	if ((fp = fopen("fncval.dat","r")) == NULL)		nrerror("Data file fncval.dat not found\n");	fgets(txt,MAXSTR,fp);	while (strncmp(txt,"Exponential Integral En",23)) {		fgets(txt,MAXSTR,fp);		if (feof(fp)) nrerror("Data not found in fncval.dat\n");	}	fscanf(fp,"%d %*s",&nval);	printf("\n%s\n",txt);	printf("%4s %7s %15s %21s \n","n","x","actual","expint(n,x)");	for (i=1;i<=nval;i++) {		fscanf(fp,"%d %f %f",&n,&x,&val);		printf("%4d %8.2f %18.6e %18.6e\n",n,x,val,expint(n,x));	}	fclose(fp);	return 0;}#undef NRANSI