does not output what i want. loop might be broken

[sharkbowman]

#include <iostream>
#include <fstream>
#include <iomanip> 
#include <string>
using namespace std;
bool validation (char c) 
{
    bool result = false;
    if (c >='A' && c <= 'Z' || c >= 'a' && c <= 'z'|| c >= '0' && c <='9' ||c =='.'||c =='-' || c =='+') result = true;
return result;
}

int main () {
    //bool ValidEmailCharacters;
	string email;
	//string anEmail;
	int s = 0;
	int e = 0;
	
	string fileName; 
	string defaultfile = "fileContainingEmails.txt";
	ifstream fin;
	ofstream fout;
	cout << "Enter your file  (ENTER for Default): " ;
	getline (cin, fileName);
	
	if (fileName.length() < 2) {
	    fileName = defaultfile;
	}

	fin.open (fileName);
    // if (!fin.good()) break;
	
	fout.open ("copyPasteMyEmail.txt");
	
	//string* email[i] = new string [newemail];     //Pulls out email from txt file
	while (true)    //reads until end of file
	{
	if (!fin.good()) break;
	
	fin >> email;
	cout << "Test" << endl;
	for (int i = 0; i > email.length(); i++)
		if (email[i] == '@')
		{
		cout << "Test1" << endl;
			for( s = i; s < email.length(); s--)
			{    
			cout << "Test2" << endl;
				if (s < 0) break;
				if (validation(email[s]) == false) break;
			}
			bool Dot = false;
				for (e = i; e < email.length(); e++)
				{
				cout << "test3" << endl;
					if (e == email.length()) break;
					if (validation(email[e]) == false) break;
					if (email[e] == '.') Dot = true;
				}
				cout << "Test4" << endl;
			string anEmail = email.substr (s, e-s);
			cout << anEmail << endl;	
		}
    }
	//fout << anEmail << endl;
   
	return 0 ;
	
}
		

[IceThatJaw]

What is it supposed to output?

[o3hC5Di1]

Hi there,

As IceThatJaw mentioned, it's usually best to give us an indication of what you expect it to output and what it is actually outputting, that makes debugging a lot easier for us.

Now, as for this line:

 //line 37
while (true)    //reads until end of file 

That's not true - the loop will keep running as long as true == true, meaning forever.
If you want to loop until the end of the file you will need to use some function of the istream that returns a value on which you can base the assumption that there is another line or not.

If you have any further questions, please elaborate a little bit on the problem.

All the best,
NwN

[Volatile Pulse]

@NwN
I believe the OP is using this line to break out of the infinite loop:
if (!fin.good()) break;

This is bad coding, but it should work. I don't understand why they have a while loop set for infinity and then break out that way. I also believe there is an issue with the validation function:

bool validation (char c) 
{
    bool result = false;
    if (c >='A' && c <= 'Z' || c >= 'a' && c <= 'z'|| c >= '0' && c <='9' ||c =='.'||c =='-' || c =='+') result = true;
return result;
}

A few things, you don't need to create a new variable, especially for bool functions. The next issue is that you're not using any parenthesis in your if statement and I don't believe it's handling it like you believe it should. Currently, every condition after the && must be true, and every condition after || can be true. The same code simplified:

bool validation (char c) 
{
    if ((c >='A' && c <= 'Z') || (c >= 'a' && c <= 'z')|| (c >= '0' && c <='9') ||c =='.'||c =='-' || c =='+') return true;
    return false;
}

Even better is to split it up:

bool validation (char c) 
{
    // Capital Letters
    if (c >='A' && c <= 'Z')
        return true;
    // Lowercase Letters
    else if (c >= 'a' && c <= 'z')
        return true;
    // Numbers
    else if (c >= '0' && c <='9')
        return true;
    // Valid Punctuation
    else if ((c =='.') || (c =='-') || (c =='+'))
        return true;
    return false;
}

[ne555]

for (int i = 0; i > email.length(); i++) That will never run. The loops executes while the condition holds.

As for the reading

	if (!fin.good()) break;
	fin >> email; //¿what if it fails here? 

Prefer while(fin>>email)

bool validation (char c) 
{
//    if ((c >='A' && c <= 'Z') || (c >= 'a' && c <= 'z')|| (c >= '0' && c <='9') ||c =='.'||c =='-' || c =='+') return true;
//    return false;
   return 
      c >='A' and c <= 'Z' //isupper
      or c >= 'a' and c <= 'z' //islower.
      //isalpha
      or c >= '0' and c <='9' //isdigit
      //isalnum
      or c =='.' or c =='-' or c =='+';
}

The parenthesis are not needed because of precedence rules

[Volatile Pulse]

I completely forgot that && and || have different precedence. I need to keep a copy of the precedence order close by.