Lecture 54 :- Factorial Of A Large Number

Calculating the factorial of a large number can lead to very large results, which may not fit into standard data types like int or long long. To handle factorials of large numbers, you can use techniques like iterative multiplication or storing the digits of the factorial in an array.

Here's a C++ code using an array to calculate the factorial of a large number:

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#include <iostream> #include <vector> void multiply(std::vector<int>& result, int x) {    int carry = 0;    for (int i = 0; i < result.size(); i++) {        int product = result[i] * x + carry;        result[i] = product % 10;        carry = product / 10;    }    while (carry) {        result.push_back(carry % 10);        carry /= 10;    } } void factorial(int n) {    std::vector<int> result;    result.push_back(1);    for (int i = 2; i <= n; i++) {        multiply(result, i);    }    std::cout << "Factorial of " << n << " is: ";    for (int i = result.size() - 1; i >= 0; i--) {        std::cout << result[i];    }    std::cout << std::endl; } int main() {    int num = 50; // Calculate factorial of 50    factorial(num);    return 0; }

Output:

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Factorial of 50 is: 30414093201713378043612608166064768844377641568960512000000000000

In this code, the multiply function is used to multiply the current result (stored in the result vector) with the number x. The factorial function calculates the factorial of the given number n using the multiply function iteratively. The result is stored in the result vector, which holds individual digits of the factorial.

Note: Calculating the factorial of very large numbers can lead to very large results, and it's essential to use appropriate data structures and techniques to handle such cases.