/* Driver for routines arcmak and arcode */#include <stdio.h>#include <stdlib.h>#include <string.h>#define NRANSI#include "nr.h"#include "nrutil.h"#define MC 512#define NWK 20#define MAXLINE 256int main(void){	int k;	unsigned long i,j,lc,lcode=MAXLINE,n,nch,nrad,nt,nfreq[257],tmp,zero=0;	unsigned char *code,mess[MAXLINE],ness[MAXLINE];	arithcode acode;	FILE *fp;	code=cvector(0,MAXLINE);	acode.ilob=lvector(1,NWK);	acode.iupb=lvector(1,NWK);	acode.ncumfq=lvector(1,MC+2);	if ((fp = fopen("text.dat","r")) == NULL)		nrerror("Input file text.dat not found.\n");	for (j=1;j<=256;j++) nfreq[j]=0;	while ((k=getc(fp)) != EOF) {		if ((k -= 31) >= 1) nfreq[k]++;	}	fclose(fp);	nch=96;	nrad=256;	/* here is the initialization that constructs the code */	arcmak(nfreq,(int)nch,(int)nrad,&acode);	/* now ready to prompt for lines to encode */	for (;;) {		printf("Enter a line:\n");		if (gets((char *)&mess[1]) == NULL) break;		n=strlen((char *)&mess[1]);		/* shift from 256 character alphabet to 96 printing characters */		for (j=1;j<=n;j++) mess[j] -= 32;		/* message initialization */		lc=1;		arcode(&zero,&code,&lcode,&lc,0,&acode);		/* here we arithmetically encode mess(1:n) */		for (j=1;j<=n;j++) {			tmp=mess[j];			arcode(&tmp,&code,&lcode,&lc,1,&acode);		}		/* message termination */		arcode(&nch,&code,&lcode,&lc,1,&acode);		printf("Length of line input, coded= %lu %lu\n",n,lc-1);		/* here we decode the message, hopefully to get the original back */		lc=1;		arcode(&zero,&code,&lcode,&lc,0,&acode);		for (j=1;j<=lcode;j++) {			arcode(&i,&code,&lcode,&lc,-1,&acode);			if (i == nch) break;			else ness[j]=(unsigned char)i;		}		if (j > lcode) nrerror("Arith. coding: Never get here");		nt=j-1;		printf("Decoded output:\n");		for (j=1;j<=nt;j++) printf("%c",(char)(ness[j]+32));		printf("\n");		if (nt != n) printf("Error ! j decoded != n input.\n");	}	free_cvector(code,0,MAXLINE);	free_lvector(acode.ncumfq,1,MC+2);	free_lvector(acode.iupb,1,NWK);	free_lvector(acode.ilob,1,NWK);	printf("Normal completion\n");	return 0;}#undef NRANSI