Alternative to if else?

[soby96]

SOi wrote this code for the recursive method and I really wanted to know if I can do this problem without using if else. what would be the appropriate replacement for if else statement?
Thanks!

 #include<iostream>
#include<cmath>;

using namespace std;

int re(int n);
float b(int n);

int main() {
	int a;
	cout << "Please entet a positive number\n";
	cin >> a;

	cout << re(a) << endl;;
	cout << b(a) << endl;


	system("pause");
	return 0;
}


float b(int n) {

	if (n == 1) {
		return 2;

	}
	else {
		return pow((-1.0), n)*sqrt(n)*b(n - 1);
	}

}

	int re(int n){

	
	
	if (n == 1) {
		return 3;
	}
	else if (n == 0) {
		return -2;
	}
	else {
		return 2 *re(n - 1) + 3* re(n - 2);
	}
	

	
}

[JLBorges]

#include <cmath>

double b( int n ) // invariant: positive n
{ return n == 1 ? 2 : std::pow( -1.0, n ) * std::sqrt(n) * b(n-1) ; }

int re( int n ) // invariant: non-negative n
{ return n == 1 ? 3 : ( n == 0 ? -2 : 2 * re(n-1) + 3 * re(n-2) ) ; }

[soby96]

Thank you very much!