sum of 2 numbers in cpp function

1#include<iostream>
2int add(int,int);
3int main()
4{
5	using namespace std;
6	int a,b;
7	cout<<"Enter first number: ";
8	cin>>a;
9	cout<<"Enter second number: ";
10	cin>>b;
11	cout<<"Sum = "<<add(a,b);
12}
13int add(int x,int y)
14{
15	return(x+y);
16}

1#include<iostream>
2using namespace std;
3int main()
4{
5	double number1,number2;
6  	double sum0;
7  	sum=number1+number2;
8  	cout<<sum;
9}