Program outline for Homework 10

/* hmw10.c -- Outline of solution for homework 10
*/

#include <stdio.h>

#define ARRAYSIZE 2000
#define LINESIZE 65

typedef char linetype[LINESIZE];

int getline(FILE * fd, char buff[], int nmax){
/* It reads a line from fd and stores up to nmax of 
* its characters to buff.
*/
char c;
int n=0;

while ((c=getc(fd))!='\n'){
if(c==EOF)return EOF;
if(n<nmax)
buff[n++]=c;
}
buff[n]='\0';
return n;
}

int getStringArray(char *filename, linetype table[], int nmax)
/* It reads up to nmax lines from file called filename and
* stores them into table. It returns the numbers of lines read
*/
{
FILE *fdu;  /* File descriptor used for filename */
int i, j;
char c;

if((fdu=fopen(filename,"r"))==NULL){
perror("fopen");
exit(1);
}
i=j=0;
while((c=getc(fdu))!=EOF){
if(i==nmax)break;  /* We have filled up the table */
if (c=='\n'){ /* We have finished reading a line */
table[i++][j]='\0';
j=0;
}else if(j<LINESIZE)
table[i][j++]=c;
}
fclose(fdu);
return i;
}

void writeStringArray(char *filename, linetype table[], int n)
/* It writes the first n lines of table into the file
* called filename
*/
{
FILE *fdu;  /* File descriptor used for filename */
int i;

if((fdu=fopen(filename,"w"))==NULL){
perror("fopen");
exit(1);
}
for(i=0;i<n;i++)
fprintf(fdu, "%s\n", table[i]);
fclose(fdu);
}

void stringBubble(linetype table[], int n){
/* This function sorts the first n lines of table.
* Here you see just the prototype, or stub, of the function.
*/
}

int stringBinary(linetype table[], int n, char who[]){
/* It searches the first n positions of table looking for who.
* It uses binary search. It returns the position where who is
* found, or -1 if not there. This is just the prototype, or stub, 
* of the function.
*/
return -1;
}

int main(void){
int n;
linetype linearray[ARRAYSIZE];
linetype who;
int where;
FILE *fdw;  /* FILE descriptor used for "who.dat" */
FILE *fda;  /* File descriptor used for "answers.dat" */

/* Read unsorted.dat into linearray and return number of lines read */
n = getStringArray("unsorted.dat", linearray, ARRAYSIZE);
if (n==0){
printf("The unsorted.dat file is empty. Good bye.\n");
exit(0);
}
/* Sort the first n lines of linearray */
stringBubble(linearray,n);
/* Save the sorted array to sorted.dat */
writeStringArray("sorted.dat",linearray,n);
/* Open for reading who.dat */
if((fdw=fopen("who.dat","r"))==NULL){
perror("fopen");
exit(1);
}
/* Open for writing answers.dat */
if((fda=fopen("answers.dat","w"))==NULL){
perror("fopen");
exit(1);
}
while (getline(fdw,who,LINESIZE-1)!=EOF){   /* Read a line from "who.dat" */
where = stringBinary(linearray,n,who);    /* See where it is in table */
fprintf(fda,"%d\n",where);            /* Write position to "answer.dat*/
}
fclose(fdw);
fclose(fda);
}