Using the header.h, input.dat, and main.c files below, answer the following questions.

Question 1: This program currently uses a library call to get the length of a string. For example: len = (int) strlen( (const char *)lineBuffer); Replace this call with your own function that is equivalent. The protoype is: int myStrlen( (const char *) stringPtr); Add this function at the end of this file. Replace the call to strlen() with calls to myStrlen(). Question 2: What gets displayed by this program if we changed line3 of input.dat to have just one number (300) ? Describe what happens and explain what you see.

******************************************************************

// header.h //

#ifndef __header_h

#define __header_h

#include //standard IO such as scanf and printf

#include //for sizeof

#include //for bool type

#include //for rand

#include

#define NOERROR 0

#define ERROR -1

#define CHAR_ERROR 0xFF

#define MAX_FILENAME_SIZE 128

#define MAX_LINE_SIZE 1024

#endif

*************************************************************************************

Input.dat

1 2 3 4

5 6 7 8

100 200

300 400

This is a line of text

-1

Final Line....

********************************************************************************

// Program : main.c

// Explanation: Shows illustrative examples of fileIO

// Program Parameters: fileName : The name of the file to read

#include "header.h"

#include

int testScanf(char *fileName);

int main(int argc, char *argv[])

{

int rc = NOERROR;

int opCode = 0;

//holds file names in string format. /Init to default file names, program arguments overide defaults

char fileName[MAX_FILENAME_SIZE] = "input.dat";

//The program can support 0, 1, or 2 arguments...Check if the first arg is provided

if ( argc != 2)

{

printf("[%s] Need a fileName ",argv[0]);

rc = ERROR;

return rc;

}

sscanf(argv[1], "%s", fileName);

printf("[%s] Entered with %i arguments, fileName:%s ", argv[0],argc,fileName);

rc = testScanf(fileName);

printf ("[%s] testScanf returns: %i ",argv[0],rc);

if (rc >=0)

rc = NOERROR;

return rc;

}

// routine: int testScanf (char *fileName)

// explanation: reads fileName and illustrates the use of fscanf and sscanf

// inputs: char *fileName: string holding the filename

// outputs: returns an ERROR or NOERROR.

int testScanf (char *fileName)

{

int rc = NOERROR;

FILE *inFile = NULL;

char lineBuffer[MAX_LINE_SIZE];

char *tmpPtr = NULL;

int number1 = 0;

int number2 = 0;

int len = 0;

int lineCount= 0;

int charCount=0;

inFile = fopen(fileName, "r");

if (inFile == NULL) {

fprintf(stderr, "ERROR: Can not open %s ", fileName);

rc = ERROR;

return rc;

}

printf("testScanf: file:%s, rc:%i, read the first number found..... ", fileName, rc);

// Let's get the first line, place it in the lineBuffer

tmpPtr = fgets(lineBuffer, MAX_LINE_SIZE, inFile);

if (tmpPtr == NULL) {

fprintf(stderr," Error from fgets : errno:%i ",errno);

rc = ERROR;

return rc;

}

len = (int) strlen( (const char *)lineBuffer);

charCount+=len;

lineCount++;

printf("line1(%i): %s ",len,lineBuffer);

tmpPtr = fgets(lineBuffer, MAX_LINE_SIZE, inFile);

len = (int) strlen( (const char *)lineBuffer);

charCount+=len;

lineCount++;

printf("line2(%i): %s ",len,lineBuffer);

//Now, read in the first number and the second from the third line

rc = fscanf(inFile, "%d %d", &number1, &number2);

if (rc == EOF) {

fprintf(stderr," Error from fscanf : errno:%i ",errno);

rc = ERROR;

return rc;

}

if (rc != 2) {

fprintf(stderr," WARNING: did not read %i varaiables ?? ",rc);

}

printf(" number of variables read from fscanf:%i, \tnumber1:%i \tnumber2:%i ",rc, number1, number2);

//Next, read the next line

tmpPtr = fgets(lineBuffer, MAX_LINE_SIZE, inFile);

if (tmpPtr == NULL) {

fprintf(stderr," Error from fgets : errno:%i ",errno);

rc = ERROR;

return rc;

}

// fgets returns a line of size 1. In fact, it is the newline. fscanf (and scanf) advances the stream only

// until it is able to get all the variables. newline allows fscanf to complete number2 but keeps the

// newline in the stream.Which is then read on our fgets....So really....this is still reading line 3

len = (int) strlen( (const char *)lineBuffer);

charCount+=len;

lineCount++;

printf("line3(%i): %s ",len,lineBuffer);

// To accommodate, we can check if all we read was a newline

if (len > 0) {

if ( *lineBuffer == ' ')

{

tmpPtr = fgets(lineBuffer, MAX_LINE_SIZE, inFile);

len = (int) strlen( (const char *)lineBuffer);

charCount+=len;

lineCount++;

printf("next line(%i): %s ",len,lineBuffer);

}

}

//THe fourth line is in lineBuffer- if this is input.dat it holds: two numbers: 300 400

//fscanf is used when the input stream is from a FILE.

//scanf is used when the input stream is stdin (we used this in our calculator programs)

//sscanf is used when the input comes from a string (i.e, string scanf )

// NOTE: scanf family functions do the same thing : convert character digits from the selected

// input stream into numbers.

rc = sscanf(lineBuffer, "%d %d", &number1, &number2);

if (rc == EOF) {

fprintf(stderr," Error from fscanf : errno:%i ",errno);

rc = ERROR;

return rc;

}

if (rc != 2) {

fprintf(stderr," WARNING: did not read %i varaiables ?? ",rc);

}

printf(" number of variables read from scanf:%i, \tnumber1:%i \tnumber2:%i ",rc, number1, number2);

printf("testScanf: exit with lineCount:%i, total number characters: %i ", lineCount, charCount);

if (inFile != NULL)

fclose (inFile);

return rc;

}