Question

C++

Using Recursion

We are going to create a (looping) menu that accesses functions that use recursion. The function headers and a description will be provided. You are responsible for defining the functions. Ensure that they each contain a base case they reach that doesn’t have a recursive function call, otherwise it’s an infinite loop! Functions must be implemented with recursion.

1. int Factorial(int arg)

   1. Returns arg! (4! Is 4 * 3 * 2 = 24)

   2. Base case is Factorial(1) returning 1

2. Int Factor(int arg)

   1. Displays the prime factors of arg, including repeats

   2. You are allowed to use your isPrime function from lab 4

   3. If factors apart from 1 and arg exist, they are <= arg/2

   4. If num%n == 0, then n is a factor of num

   5. Base case: Factor(n), where n is prime, which just displays the prime with cout

3. string ObliterateString(string arg)

   1. Takes the argument and removes a random character from it

   2. New string is displayed then used for recursive call

   3. Base case: ObliterateString(“”) has no string to obliterate, no output necessary.

Answer 1

#include <iostream >


using namespace std ;


int factorial( int arg ){

    if( arg == 1 )
         return 1;

    else
return (arg * factorial( arg- 1 ) ) ;


}

int isPrime( int arg ){

    for (int i = 2; i <= arg/2; ++i) {

        if( arg% i == 0 )
            return 0  ;
        else return  1 ;

    }
}


int Factor(   int arg ) {
cout<<" The prime factors of number   are :" ;
    for (int i = 2; i < arg   ; ++i) {
        // since 1 is neither prime nor composite
        // thats why starting loop from 2
        if( arg % i == 0 ) {
            if (isPrime(i))

                cout << i << "  ";

        }
    }

}

int main(){


cout<< " enter an positive integer number "<< endl ;
    int value ;
    cin>> value ;
   int fact =   factorial(value );
    cout<< " The factorial of entered number is "<< fact << endl ;

        Factor(value );
    return 0 ;


}