I'm trying to add subtract and multiply numbers with huge decimals C++.
Example:
4125487821547.87879845215584844588 - 354556689.899455132265468
What I figured so far is that I need to save inputs as a string, but not sure how to proceed after that.
Appreciate the help in advance Thanks
You need a big integer class or library. There are several implementations available, just to give you an overview on how to use such an external dependency, here is a solution based on Boost:
#include <boost/multiprecision/cpp_int.hpp>
using BigInt = boost::multiprecision::cpp_int;
You can now construct instances by passing string or integral literals to the constructor and do all standard arithmetic operations with these objects, e.g.
const BigInt i("8787984521558484092344588");
const BigInt j("32308942039402934");
std::cout << i - j << "\n";
One nice detail of such classes is that they usually demonstrate one of the few justified scenarios for non-explicit constructors with one argument, i.e., for the sake of smooth interoperability with builtin integral types. Example:
int n = 42;
// Use builtin ints like BigInts via implicit BigInt(int) ctor:
std::cout << (i + n)/(j % 3) << "\n";
You only need the Boost headers for these snippets, no linkage is required. Check out the docs when proceeding with this library.