Question

I need help debugging this C++ prgram. What Am i doing wrong?

//********************************************************

// This program reads two input files whose lines are //ordered by a key data field. This program should merge //these two files, writing an output file that contains //all lines from both files ordered by the same key field.

//

//*********************************************************

#include <iostream>

#include<string>

#include<fstream>

//prototype

void mergeTwoFiles (ifstream&,ifstream&, ofstream&);

using namespace std;

int main()

{string inFile1,inFile2,outFile;

// input and output files

ifstream in1;

ifstream in2;

ofstream out;

// get two input files from user

cout<<"enter input file 1:";

cin>>inFile1;

cout<<"enter second input file";

cin>>inFile2;

cout<<"enter output file";

cin>>outFile;

//prepare files

in1.open(inFile1);

if (in2.fail())

{

cerr<< "can't open" << inFile2 << "for input.";

system("pause");

return EXIT_FAILURE;

}

out.open(outFile);

if(out.fail())

{

cerr <<" Can't open"<< outFile << "for output."<<;

system("pause");

return EXIT_FAILURE;

}

//Merge 2 files

mergeTwoFiles(in1,in2,out);

// close files

in1.close();

in2. close();

out.close();

//Pause

system("pause");

return 0;

}

void mergeTwoFiles(ifstream &in1, ifstream &in2, ofstream &out)

{

string str1,str2;

//read data

getline(in1, str1);

getline(in2, str2);

//repeat loop

while((!in1.eof()) && (!in2.eof()))

{

//if the line from file 1 is smaller

if(str1<=str2)

out<< str1 << endl;

//read a new line

getline(in1,str1);

}

//if the line from file 2 is smaller than file 1

else

{

//write file 2's line to the output

out<< str2 << endl;

getline(in2, str2);

}

}

// write remaining lines from file 2

while(!in1.eof())

{

out<< str2 <<endl;

getline(in2, str2);

}

if(str2 !="")

out<< str2 <<endl;

//end of merge function

Answer 1

If you have any doubts, please give me commment...

//********************************************************

// This program reads two input files whose lines are //ordered by a key data

// field. This program should merge //these two files, writing an output file

// that contains //all lines from both files ordered by the same key field.

//

//*********************************************************

#include <iostream>

#include <string>

#include <fstream>

#include <cstdlib>

// prototype

using namespace std;

void mergeTwoFiles(ifstream &, ifstream &, ofstream &);

int main() {

string inFile1, inFile2, outFile;

// input and output files

ifstream in1;

ifstream in2;

ofstream out;

// get two input files from user

cout << "enter input file 1: ";

cin >> inFile1;

cout << "enter second input file: ";

cin >> inFile2;

cout << "enter output file: ";

cin >> outFile;

// prepare files

in1.open(inFile1.c_str());

in2.open(inFile2.c_str());

if (in1.fail()) {

cerr << "can't open" << inFile1 << "for input.";

system("pause");

return EXIT_FAILURE;

}

if (in2.fail()) {

cerr << "can't open" << inFile2 << "for input.";

system("pause");

return EXIT_FAILURE;

}

out.open(outFile.c_str());

if (out.fail()) {

cerr << " Can't open" << outFile << "for output." << endl;

system("pause");

return EXIT_FAILURE;

}

// Merge 2 files

mergeTwoFiles(in1, in2, out);

// close files

in1.close();

in2.close();

out.close();

// Pause

system("pause");

return 0;

}

void mergeTwoFiles(ifstream &in1, ifstream &in2, ofstream &out) {

string str1, str2;

// read data

getline(in1, str1);

getline(in2, str2);

// repeat loop

while ((!in1.eof()) && (!in2.eof())) {

// if the line from file 1 is smaller

if (str1 <= str2) {

out << str1 << endl;

// read a new line

getline(in1, str1);

}

// if the line from file 2 is smaller than file 1

else {

// write file 2's line to the output

out << str2 << endl;

getline(in2, str2);

}

}

// write remaining lines from file 2

while (!in1.eof()) {

out << str1 << endl;

getline(in1, str1);

}

// write remaining lines from file 2

while (!in2.eof()) {

out << str2 << endl;

getline(in2, str2);

}

// end of merge function

}