char* two_complement(int number, char* sign_mag_array){

	int first_one_flag = 0;

	if(number > 0){
		cout << "positive number" << endl;
		return sign_mag_array;
	}

	if(number < 0){
		for(int q = 7; q >= 0; q--){
			if(first_one_flag == 1){				// negate the rest regularly
				cout << "negate normally " << endl;

				if(sign_mag_array[q] == '0'){
					sign_mag_array[q] = 'F';
				}
				if(sign_mag_array[q] == '1'){
					sign_mag_array[q] = 'E';
				}
				if(sign_mag_array[q] == '2'){
					sign_mag_array[q] = 'D';
				}
				if(sign_mag_array[q] == '3'){
					sign_mag_array[q] = 'C';
				}
				if(sign_mag_array[q] == '4'){
					sign_mag_array[q] = 'D';
				}
				if(sign_mag_array[q] == '5'){
					sign_mag_array[q] = 'A';
				}
				if(sign_mag_array[q] = '6'){
					sign_mag_array[q] = '9';
				}
				if(sign_mag_array[q] == '7'){
					sign_mag_array[q] = '8';
				}
				if(sign_mag_array[q] == '8'){
					sign_mag_array[q] = '7';
				}
				if(sign_mag_array[q] = '9'){
					sign_mag_array[q] = '6';
				}
				if(sign_mag_array[q] == 'A'){
					sign_mag_array[q] = '5';
				}
				if(sign_mag_array[q] == 'B'){
					sign_mag_array[q] = '4';
				}
				if(sign_mag_array[q] = 'C'){
					sign_mag_array[q] = '3';
				}
				if(sign_mag_array[q] == 'D'){
					sign_mag_array[q] = '2';
				}
				if(sign_mag_array[q] == 'E'){
					sign_mag_array[q] = '1';
				}
				if(sign_mag_array[q] == 'F'){
					sign_mag_array[q] = '0';
				}
			}


			if(sign_mag_array[q] == '0' && first_one_flag == 0){
				cout << "no one's showed up yet --> 0 " << endl;
			}
			else{												// first '1' in binary seen. special negating
				//first_one_flag = 1;
				cout << "first 1 is seen, leave first 1 the same " << endl;

				if(sign_mag_array[q] == '1'){
					sign_mag_array[q] = 'F';
				}
				if(sign_mag_array[q] == '2'){
					sign_mag_array[q] = 'E';
				}
				if(sign_mag_array[q] == '3'){
					sign_mag_array[q] = 'D';
				}
				if(sign_mag_array[q] == '4'){
					sign_mag_array[q] = 'C';
				}
				if(sign_mag_array[q] == '5'){
					sign_mag_array[q] = 'B';
				}
				if(sign_mag_array[q] == '6'){
					sign_mag_array[q] = 'A';
				}
				if(sign_mag_array[q] = '7'){
					sign_mag_array[q] = '9';
				}
				if(sign_mag_array[q] == '8'){
					sign_mag_array[q] = '8';
				}
				if(sign_mag_array[q] == '9'){
					sign_mag_array[q] = 'K';
				}
				if(sign_mag_array[q] == 'A'){
					sign_mag_array[q] = '6';
				}
				if(sign_mag_array[q] == 'B'){
					sign_mag_array[q] = '5';
				}
				if(sign_mag_array[q] == 'C'){
					sign_mag_array[q] = '4';
				}
				if(sign_mag_array[q] == 'D'){
					sign_mag_array[q] = '3';
				}
				if(sign_mag_array[q] == 'E'){
					sign_mag_array[q] = '2';
				}
				if(sign_mag_array[q] == 'F'){
					sign_mag_array[q] = '1';
				}
			}
		}
	}
	return sign_mag_array;
}