Download the "bigint.h" header .Then #include it inside your code:
Command to compile cpp files g++ bigint.hpp bigint.cpp SampleCode.cpp
#include "bigint.h" // the actual path may vary
bigint n1; //n1 defined with value 0
bigint n2(123); //n2 defined with value int value
bigint n3((long long int)1234567898765432); //n3 defined with value long long int value
bigint n4("7832467326423873423435"); //n4 defined with string value
bigint n5(n3); //n5 defined with values of n3
bigint n6 = bigint::to_bigint(num1); //converting int to bigint
bigint n7 = bigint::to_bigint(num2); //converting long long int to bigint
bigint n8 = bigint::to_bigint(str1); //converting string to bigint
cout << "Addition: " << n1 + n2 << endl; //Addition
cout << "Subtraction: " << n2 - n1 << endl; //subtraction
cout << "Multiplication: " << n1 * n2 << endl; //Multiplication
cout << "Division: " << n4 / n2 << endl; //Division
cout << "n2 + 5: " << n2 + 5 << endl;
cout << "n2 - 5: " << n2 - 5 << endl;
cout << "n2 * 5: " << n2 * 5 << endl;
cout << "n2 / 5: " << n2 / 5 << endl;
cout << "5 + n2: " << 5 + n2 << endl;
cout << "5 - n2: " << 5 - n2 << endl;
cout << "5 * n2: " << 5 * n2 << endl;
cout << "5 / n2: " << 5 / n2 << endl;
cout<<"PreIncrement: "<<++n2<<endl;
cout<<"PreDecrement: "<<--n2<<endl;
cout<<"PostIncrement: "<<n2++<<endl;
cout<<"PostDecrement: "<<n2--<<endl;
cout<<"Check n3 != n5: "<<(bool)(n3 != n5)<<endl; //Checking if value of both are different
cout<<"Check n3 == n5: "<<(bool)(n3 == n5)<<endl; //Checking if value of both are same
n3 += n2;
cout<<"n3 += n2: "<<n3<<endl;
n3 -= n2;
cout<<"n3 -= n2: "<<n3<<endl;
n3 *= n2;
cout<<"n3 *= n2: "<<n3<<endl;
n3 /= n2;
cout<<"n3 /= n2: "<<n3<<endl;
cout << "Maximum: " << bigint::max(n1, n2) << endl; //Maximum of two Numbers
cout << "Minimum: " << bigint::min(n1, n2) << endl; //Minimum of two Numbers
cout << "absolute: " << bigint::abs(n1) << " " << bigint::abs(n2) << endl; //Absolute value of a number
cout << "Factorial: " << bigint::fact(n1) << " " << bigint::fact(n2) << endl; //Factorial of a number
cout << "Reverse: " << bigint::reverse(n3) << endl; //Reverse a number
cout << "isPalindrome: " << (bool)bigint::isPalindrome(n9) << endl; //Checking if a number is palindrome
cout << "Power: " << bigint::pow(n3, n2) << endl; //finds int(X) to the power int(Y)