Code to output pictures of large penises

#include<iostream>
#include<fstream>
#include<cstdlib>
#include<string>
#include<cmath>
#include <stdlib.h>

using namespace std;


void channelDecode(const string & input, string & fixed)
{
	char A = 0;

	for (unsigned int n = 0; n < input.size() - 1; n++)
	{
		A = A + input[n];
	}

	if (A == input[input.size() - 1] )
	{
		fixed = input.substr(0, input.size() -1);
	}
	else
	{
		fixed = "Packet was corrupted and could not be decoded.";
	}
return;
}


int parseLine(const string & line, const string & key)
{
	int number1 = line.find(key);
	int number2 = line.length();
	if (number1 < 0 || number1 > number2)
	{
		return -9999;
	}
	string lineNew = line.substr(number1);
return atoi(line.substr(number1 + 3, lineNew.find(' ') ).c_str() );
}

string removeUnder(const string & input)
{
	string inF = input;
	for(int i = 0; i < input.size(); i++)
	{
		if( input [i] == '_')
		{
			inF[i] = ' ';
		}
		else
		{
			inF[i] = input[i];
		}
	}
return inF;
}

int main()
{
	ifstream infile("beacon.txt");
	ofstream outfile("beacon_clear.txt");
	string input;
	string fixed;

	bool num = true;

	do
	{
		getline(infile, input);
		if (infile.eof())
		{
			num = false;
		}
		else
		{
			fixed = input;
			channelDecode(input, fixed);
			outfile << fixed << endl;
		}
	}
	while(num);
	infile.close();
	outfile.close();

	string bcline, iline, name, key, intitle, bctitle;
	int components, val;

	ifstream beacon("beacon_clear.txt");
	ofstream result("result.txt");
	ifstream index("dataIndex.txt");

	while(getline(beacon, bcline))
	{
		ifstream index("dataIndex.txt");
		if (bcline != "Packet was corrupted and could not be decoded.")
		{
			bcline.append(" ");
			bctitle = bcline.substr(0, bcline.find(' '));
			index >> intitle;
			while (intitle != bctitle)
			{
				index >> intitle;
			}
			getline(index, iline);
			components = atoi(iline.c_str());
			index.close();
			result << removeUnder(intitle) << "\n";
			iline = iline.substr(3);

			for (int i = 0; i < components; i++)
			{
				key = iline.substr(0, 2);
				val = parseLine(bcline, key);
				iline = iline.append(" ");
				iline = iline.substr(iline.find(' ') + 1);
				name = iline.substr(0, iline.find(' '));
				iline = iline.substr(iline.find(' ') + 1);
				result << removeUnder(name) << ": " << val << "\n";
			}
		}
		result << "\n";
	}
index.close();
result.close();

return 0;
}