Long multiplication and karatsuba multiplication. Should be done in C++

Needs to read two digit strings a and b. Strore in a vector, each. The numbers a and b can be very large, for example, they can be thousands of digits.

Need an algorithm that will multiplty a and b by brute force time complexity of (n^2). Also known as "third grade multiplication". and output the result.

Sould also have an addition function for when to add the multiplications.

Need an algorithm that will multiply a and b using the karatsuba algorthim, also known as the "divide and conquer". and output the result.