// OLA206 BY student name, CSCI2170-sec, Due: mm/dd/yy
// PROGRAM ID: binadd.cpp / Binary Number Addition Program
// AUTHOR: student name
// INSTALLATION: MIDDLE TENNESSEE STATE UNIVERSITY
// REMARKS:  Adds two or more binary numbers appearing as command-line
// arguments.  The resulting sum is sent to stdout.  The arguments are
// assumed to be well-formed (valid) binary numbers; no error checking
// is performed on the arguments.
//
//    For example:       binadd 100 1 1101 0
//    should print       10010
//
//  .    1    .    2    .    3    .    4    .    5    .    6    .    7    .
//3456789012345678901234567890123456789012345678901234567890123456789012345

#include <iostream>
#include <cstring>

using namespace std;

const int MAX_DIGITS = 36;  // Maximum digits in (output) sum

bool Badd( const char augend[], const char addend[], char sum[] );
//         IN                   IN                   OUT


int main( int argc, char* argv[] )
//        IN        IN
{
	char   partialSum[MAX_DIGITS+1];   // Partial sum of the binary numbers
	char   sum[MAX_DIGITS+1];          // Sum of the binary numbers
	bool   noError;                    // No error flag

	// Exit if insufficient arguments were supplied.
	if (argc < 3)
	{
		cout << "Error: insufficient arguments.\n";
		return 1;
	}

	// Add together the first two binary numbers on the command-line.
	noError = Badd( argv[1], argv[2], sum );

	// Add any additional binary numbers to the partial sum.
	for (int counter = 3; noError && counter < argc; counter++)
	{
		strcpy( partialSum, sum );
		noError = Badd( partialSum, argv[counter], sum );
	}

	// Print answer on standard output.
	if (noError)
		cout << sum << endl;
	else
		cout << 'E' << endl;

	return 0;
} // end main


bool Badd( const char augend[], const char addend[], char sum[] )
//         IN                   IN                   OUT
// Pre:  augend and addend are strings representing valid binary numbers.
// Post: sum is a string representing the sum of augend + addend.
// Returns true if successful in addition, false otherwise.
{
	int x, carry = 0;
	for(int i = 0; i < argc-1; i++)
	{
    if(augend[i]==1 && addend[i]==1 && carry ==1)
		{
		sum[x]=1;
		carry=1;
		}
    else if(augend[i]==1 && addend[i]==1 && carry ==0)
		{
		sum[x]=0;
		carry=1;
		}
	else if(augend[i]==0 && addend[i]==1 && carry ==0)
		{
		sum[x]=1;
		carry=0;
		}
	else if(augend[i]==0 && addend[i]==1 && carry ==1)
		{
		sum[x]=0;
		carry=1;
		}
	else if(augend[i]==1 && addend[i]==0 && carry ==1)
		{
		sum[x]=0;
		carry=1;
		}
	else if(augend[i]==1 && addend[i]==0 && carry ==0)
		{
		sum[x]=1;
		carry=0;
		}
	else if(augend[i]==0 && addend[i]==0 && carry ==1)
		{
		sum[x]=1;
		carry=0;
		}
	else if(augend[i]==0 && addend[i]==0 && carry ==0)
		{
		sum[x]=0;
		carry=0;
		}
	x++;
	}
	sum[0] = '0';
	sum[1] = '\0';

	return true;
} // end Badd