EXPONENTIAL FINDING IN CPP SOURCE CODE

/*EXPONENTIAL.CPP*/
#include "calculator.h"
#include <iostream>
using namespace std;
#include <math.h>
void ScientificCalculator::exponential()
{
 cout<<"Enter the number: "<<endl;
 cin>>a;
 double(a);
 cout<<"The answer is "<<exp(a)<<endl;
}