C$++$ please

#pragma once

#include

#include

#include

#include

namespace ds

$\{$

class BigInt

$\{$

public:

BigInt$()=$ default;

explicit BigInt$($std::string str$)$;

$//$ Since we are not managing dynamic memory, we don't need the rule of three!

void output$()\{$ std::cout $<<*$this $<<$ std::endl;$\}$

$//$ BONUS: TODO: Implement the $*$ operator

BigInt operator$+($const BigInt& other$)$ const

$\{$

BigInt result;

BigInt::add$(*$this$,$ other, result$)$;

return result;

$\}$

BigInt operator$-($const BigInt& other$)$ const

$\{$

BigInt result;

if $(*$this $>=$ other$)$

$\{$

BigInt::subtract$(*$this$,$ other, result$)$;

$\}$

else

$\{$

BigInt::subtract$($other$,*$this$,$ result$)$;

$\}$

return result;

$\}$

$//$ While this function strictly isn't required, it is helpful for $`-`$ operator

bool operator$>=($const BigInt& other$)$ const;

$//$ This operator is used in testing $/$ implementing output

friend std::ostream& operator$<<($std::ostream& os$,$ const BigInt& d$)$

$\{$

$//$ TODO: Implement this

$\}$

private:

$//$ Add and Subtract are private as they are internal implementation details

void add$($const BigInt& a$,$ const BigInt& b$,$ BigInt& result$)$ const;

void subtract$($const BigInt& a$,$ const BigInt& b$,$ BigInt& result$)$ const;

std::vector digits;

$\}$;

$\}$

ds::BigInt::BigInt$($std::string str$)$

$\{$

$//$ TODO: Implement this

$//$ HINT: Can you use std::transform?

$\}$

void ds::BigInt::add$($const BigInt& a$,$ const BigInt& b$,$ BigInt& result$)$ const

$\{$

$//$ TODO: Implement this

$\}$

$/**$

$*$ @brief Subtract two BigInts

$*$ @param a the first BigInt

$*$ @param b the second BigInt

$*$ @param result the result of the subtraction

$*$

$*$ @pre a $>=$ b

$*/$

void ds::BigInt::subtract$($const BigInt& a$,$ const BigInt& b$,$ BigInt& result$)$ const

$\{$

$//$ TODO: Implement this

$\}$

$//$ Needed to implement absolute difference

bool ds::BigInt::operator$>=($const BigInt& other$)$ const

$\{$

$//$ TODO: Implement this

$\}$