In C++, we can use large numbers by using the boost library. This C++ boost library is widely used library. This is used for different sections. It has large domain of applications. For example, using boost, we can use large number like 264 in C++.
Here we will see some examples of boost library. We can use big integer datatype. We can use different datatypes like int128_t, int256_t, int1024_t etc. By using this we can get precision up to 1024 easily.
At first we are multiplying two huge number using boost library.
Example
#include<iostream>
#include <boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
using namespace std;
int128_t large_product(long long n1, long long n2) {
int128_t ans = (int128_t) n1 * n2;
return ans;
}
int main() {
long long num1 = 98745636214564698;
long long num2 = 7459874565236544789;
cout << "Product of "<< num1 << " * "<< num2 << " = " <<
large_product(num1,num2);
}
Output
Product of 98745636214564698 * 7459874565236544789 =
736630060025131838840151335215258722
Another kind of datatype is that Arbitrary Precision Datatype. So we can use any precision using cpp_int datatype. It automatically assigns precision at runtime.
Example
#include<iostream>
#include <boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
using namespace std;
cpp_int large_fact(int num) {
cpp_int fact = 1;
for (int i=num; i>1; --i)
fact *= i;
return fact;
}
int main() {
cout << "Factorial of 50: " << large_fact(50) << endl;
}
Output
Factorial of 50:
30414093201713378043612608166064768844377641568960512000000000000