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ok so i need to ask the user for a file to use for the input, then i need to read the input a line at a time, because i am trying to take postfix expressions from the file and evaluate them then return the result in the user's choice of a text file or just on the screen. The problem i am having now is i dont know how to take the user's input from their file and read a line at a time and put it into a stack im so confused. any help would be great thanks.

/************************************************************************
	Postfix Evaluation Program
	Version 1.0
	
	This is a program that takes a file from the user and evaluates postfix expressions from the file.
		 
	Source File:  postfixEval.cpp

*************************************************************************/
#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
//include stack
using namespace std;

int main()
{
	char inFileName[60];
	string outFileName;

	cout << "Enter the name of the input file --> ";
	cin >> inFileName;
	cout << endl << endl;

	ifstream postfixFile;  // Input filestream variable
	
	// Attempt to open the file
	postfixFile.open(inFileName);
	// Check to make sure it opened
	if( postfixFile.fail() )
	{
		cout << "Error opening input file." << endl;
		exit(EXIT_FAILURE);
	}

	while( !postfixFile.eof() )
	{
		//have user input placed into stack here!!
	}
			
	cout << "The file contained " << numChars << " characters." << endl;
	
	// Close the file -- necessary if the file is to be reread
	myIn.close();
	
	cout << "Enter the name of the output file --> ";
	cin >> outFileName;
	cout << endl << endl;
	
	ofstream resultFile; // Output filestram variable
	// Attempt to open the file
	resultFile.open(outFileName.c_str());  // Filename must be a cstring
	// Check to make sure it opened
	if( resultFile.fail() )
	{
		cout << "Error opening output file." << endl;
		exit(EXIT_FAILURE);
	}

	// Write some stuff to the file
	myOut << "This is written to the file." << endl;
	
	// Be sure to close the file -- otherwise it may not be created
	myOut.close();
	
	return EXIT_SUCCESS;
}
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Last Post by v3ga
0

Where's myIn and myOut declared?

its not it myin should be postfixFile and myout should be resultFile

0

Use getline.. myIn.getline(expression,SIZE,delimiter). SIZE is no of characters, delimiter denotes end of input default '\n'

Edited by v3ga: n/a

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