Question

C++

Create three recursive functions that accomplish the following:

Recursive Power Function this function will raise a number to a power. The function should accept two arguments, the number to be raised and the exponent. Assume that the exponent is a non-negative integer.

String Reverser function that accepts a string object as its argument and prints the string in reverse order.

Sum of Numbers this function accepts an integer argument and returns the sum of all the integers from 1 up to the number passed as an argument. For example, if 10 is passed as an argument the function will return the sum of 1, 2, 3, 4, 5 ... 10. Main should call each of the functions to show that they work correctly.

Answer 1

#include <iostream>
#include <string>
using namespace std;
float power(float x, float y)
{
   // indeterminate form
   if (x == 0 && y == 0)
   {
       return -1;
   }
   // if x is 0
   else if (x == 0)
   {
       return 0;
   }
   // if y is 0
   else if (y == 0)
   {
       return 1;
   }
   //else
   return x*power(x,y-1);
}

void reverse(const string& str)
{
   size_t len = str.size();
   if (len == 0)
   {
       return;
   }
   else if(len == 1)
   {
cout << str << endl;
   }
else
{
cout << str[len-1];
reverse(str.substr(0, len-1));
}
}

int sum(int n)
{
   // if number is negative return 0
   if (n <= 0)
   {
       return 0;
   }
   //else
   return n+sum(n-1);
}

int main()
{
   cout<<"power(0,0): "<<power(0,0)<<endl;
   cout<<"power(0,4): "<<power(0,4)<<endl;
   cout<<"power(4,0): "<<power(4,0)<<endl;
   cout<<"power(2,3): "<<power(2,3)<<endl;

   reverse("");
   reverse("ramvishvas");

   cout<<" sum(10): "<<sum(10)<<endl;
   return 0;
}