iterative_factorial.cpp File Reference

Iterative implementation of Factorial More...

#include <cassert>
#include <cstdint>
#include <exception>
#include <iostream>

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Namespaces
namespace	math
	for IO operations

Functions
uint64_t	math::iterativeFactorial (uint8_t n)
	Calculates the factorial iteratively.
static void	test ()
	Self-test implementations to test iterativeFactorial function.
int	main ()
	Main function.

Detailed Description

Iterative implementation of Factorial

Author

Renjian-buchai

Calculates factorial iteratively.

\[n! = n\times(n-1)\times(n-2)\times(n-3)\times\ldots\times3\times2\times1 = n\times(n-1)!\]

for example: \(4! = 4\times3! = 4\times3\times2\times1 = 24\)

Function Documentation

main()

int main

(

void

)

Main function.

Returns

0 on exit

           {
    test();  // Run self-test implementation
    return 0;
}

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test()

static void test ( )

static

Self-test implementations to test iterativeFactorial function.

Note

There is 1 special case: 0! = 1.

                   {
    // Special case test
    std::cout << "Exception case test \n"
                 "Input: 0 \n"
                 "Expected output: 1 \n\n";
    assert(math::iterativeFactorial(0) == 1);
 
    // Base case
    std::cout << "Base case test \n"
                 "Input: 1 \n"
                 "Expected output: 1 \n\n";
    assert(math::iterativeFactorial(1) == 1);
 
    // Small case
    std::cout << "Small number case test \n"
                 "Input: 5 \n"
                 "Expected output: 120 \n\n";
    assert(math::iterativeFactorial(5) == 120);
 
    // Medium case
    std::cout << "Medium number case test \n"
                 "Input: 10 \n"
                 "Expected output: 3628800 \n\n";
    assert(math::iterativeFactorial(10) == 3628800);
 
    // Maximum case
    std::cout << "Maximum case test \n"
                 "Input: 20 \n"
                 "Expected output: 2432902008176640000\n\n";
    assert(math::iterativeFactorial(20) == 2432902008176640000);
 
    // Exception test
    std::cout << "Exception test \n"
                 "Input: 21 \n"
                 "Expected output: Exception thrown \n";
 
    bool wasExceptionThrown = false;
    try {
        math::iterativeFactorial(21);
    } catch (const std::invalid_argument&) {
        wasExceptionThrown = true;
    }
    assert(wasExceptionThrown);
 
    std::cout << "All tests have passed successfully.\n";
}

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