how to cast value to double in cpp code example

Example 1: c++ changing string to double

#include <iostream>
using namespace std;
int main() {
   char s[20] = "18.2894 is a number";
   char *p;
   double result;
   result = strtod(s, &p);
   cout<<"The number after conversion of string : "<<result;
   return(0);
}

Example 2: casting to a double in c++

double x;
x = (double) 25;