Big number in C++

Question

I am trying to place a big number in a C++ variable. The number is 600851475143

I tried unsigned long long int but got an error saying it the constant was too big. I then tried a bigInt library called BigInt -> http://mattmccutchen.net/bigint/

The problem is I can't compile the code as I get many errors regarding the lib.

undefined reference to `BigInteger::BigInteger(int)' <-- lot's of these.

Here is my code so far:

#include "string"
#include "iostream"       
#include "bigint/NumberlikeArray.hh"
#include "bigint/BigUnsigned.hh"
#include "bigint/BigInteger.hh"
#include "bigint/BigIntegerAlgorithms.hh"
#include "bigint/BigUnsignedInABase.hh"
#include "bigint/BigIntegerUtils.hh"
using namespace std;

int main() {

    //unsigned long int num = 13195;
    //unsigned long long int num = 600851475143;
    BigInteger num = 13195;
    int divider = 2;

    //num = 600851475143;

    while (1) {
        if ((num % divider) == 0) {
            cout << divider << '\n';
            num /= divider;
        }
        else
            divider++;

        if (num == 1)
            break;
    }
}

If I put a smaller number and don't use the BigInt lib this program runs fine. Any help will be appreciated :D

Answer 1

You can specify an integer literal as long by the suffix L.
You can specify an integer literal as long long by the suffix LL.

#include <iostream>

int main()
{
    long long num = 600851475143LL;

    std::cout << num;
}