bigint::bigvalue_t trim_zeros(bigint::bigvalue_t that){
bigint::bigvalue_t result;
bigint::bigvalue_t::reverse_iterator rit2 = that.rbegin();
bigint::bigvalue_t::iterator it = result.begin();
bool high_order = true;
//int i = 0;
while(rit2 != that.rend()){
while(high_order){
if(*rit2 != 0){
high_order = false;
} else{
++rit2;
}
if (rit2 == that.rend()) break;
}
if (rit2 != that.rend()){
it = result.insert(it, *rit2);
it = result.begin();
++rit2;
}
}
if (result.size() == 0){
result.push_back(0);
//result.negative = false;
}
return result;
}
//returns true if left is > right, false if left <= right
bool do_bigless
(const bigint::bigvalue_t left, const bigint::bigvalue_t right){
if (left.size() > right.size())
return true;
else if(left.size() < right.size())
return false;
bigint::bigvalue_t::const_reverse_iterator
left_digit = left.rbegin();
bigint::bigvalue_t::const_reverse_iterator
right_digit = right.rbegin();
bool abs_val_greatest = false;
while (left_digit != left.rend()){
if (*left_digit > *right_digit){
return true;
} else if (*left_digit < *right_digit){
break;
}
++left_digit;
++right_digit;
}
return abs_val_greatest;
}
bigint::bigvalue_t trim(bigint::bigvalue_t result) {
for(auto it = result.rbegin(); it != result.rend()
and *it == 0; ++it) {
result.pop_back();
}
if(result.empty()) result.push_back(0);
return result;
}
bigint::bigvalue_t do_bigsub(const bigint::bigvalue_t& top,
const bigint::bigvalue_t& bottom) {
bigint::bigvalue_t diff{};
auto itor_top = top.rbegin();
auto itor_bottom = bottom.rbegin();
// use signed integers so we don't end up with -1 == 255
int digit_top{0};
int digit_bottom{0};
int digit_diff{0};
int borrow{0};
while (itor_top != top.rend()) {
digit_top = static_cast<int>(*itor_top++);
if (itor_bottom == bottom.rend()) {
digit_bottom = 0;
} else {
digit_bottom = static_cast<int>(*itor_bottom++);
}
digit_top -= borrow;
if (digit_top < digit_bottom) {
borrow = 1;
digit_top += 10;
} else {
borrow = 0;
}
digit_diff = digit_top - digit_bottom;
/* cout << "do_bigsub():digit:"<< static_cast<unsigned>(digit_top);
cout << " - " << static_cast<unsigned>(digit_bottom);
cout << " = " << static_cast<unsigned>(digit_diff) << endl;*/
diff.insert(diff.begin(), digit_diff);
}
/* cout << "do_bigsub(): ";
for (auto i : top) cout << static_cast<unsigned>(i);
cout << " - ";
for (auto i : bottom) cout << static_cast<unsigned>(i);
cout << " = ";
for (auto i : diff) cout << static_cast<unsigned>(i);
cout << endl;*/
// Trim trailing zeros
for (auto i : diff) {
if (i == 0) diff.pop_back();
else break;
}
return diff;
}
bigint::bigvalue_t do_bigmult(const bigint::bigvalue_t& top,
const bigint::bigvalue_t& bottom) {
bigint::bigvalue_t product{};
auto itor_bottom = bottom.rbegin();
while (itor_bottom != bottom.rend()) {
unsigned char carry {0};
auto itor_top = top.rbegin();
while (itor_top != top.rend()) {
unsigned char digit = *itor_top++ * *itor_bottom++;
digit += carry;
product.insert(product.begin(), digit % 10);
carry = digit / 10;
}
}
return product;
}
bigint::bigvalue_t do_bigadd(const bigint::bigvalue_t& top,
const bigint::bigvalue_t& bottom) {
bigint::bigvalue_t sum{}; // return value
bigint::digit_t digit_sum{0}; // digit marker
bigint::digit_t digit_top{0};
bigint::digit_t digit_bottom{0};
bigint::digit_t carry{0}; // carryover marker
// iterators
auto itor_top = top.rbegin();
auto itor_bottom = bottom.rbegin();
while(itor_top != top.rend()) {
digit_top = static_cast<unsigned>(*itor_top++);
if (itor_bottom == bottom.rend()) {
digit_bottom = 0;
} else {
digit_bottom = static_cast<unsigned>(*itor_bottom++);
}
digit_sum = digit_bottom + digit_top + carry;
if (digit_sum > 9) {
carry = 1;
digit_sum -= 10;
} else {
carry = 0;
}
sum.insert(sum.begin(), digit_sum);
}
cout << "do_bigadd(): ";
for (auto i : top) cout << static_cast<unsigned>(i);
cout << " + ";
for (auto i : bottom) cout << static_cast<unsigned>(i);
cout << " = ";
for (auto i : sum) cout << static_cast<unsigned>(i);
cout << endl;
for (auto i : sum) {
if (i == 0) sum.pop_back();
else break;
}
return sum;
}
