sum of two numbers in c++ code example

Example 1: sum of 2 numbers in cpp

#include<iostream>
int add(int,int);
int main()
{
	using namespace std;
	int a,b;
	cout<<"Enter first number: ";
	cin>>a;
	cout<<"Enter second number: ";
	cin>>b;
	cout<<"Sum = "<<add(a,b);
}
int add(int x,int y)
{
	return(x+y);
}

Example 2: c++ sum up numbers

// Method 1: Mathematical -> Sum up numbers from 1 to n 
int sum(int n){
	return (n * (n+1)) / 2;
}

// Method 2: Using a for-loop  -> Sum up numbers from 1 to n 
int sum(int n){
	int tempSum = 0; 
  	for (int i = n; i > 0; i--){
     	tempSum += i;  
    }
  	return tempSum; 
}

// Method 3: Using recursion -> Sum up numbers from 1 to n 
int sum(int n){
	return n > 0 ? n + sum(n-1) : 0; 
}

Example 3: add two numbers in c++

#include <iostream>
using namespace std;

//function declaration
int addition(int a,int b);

int main()
{
	int a,b;	//to store numbers
	int add;	//to store addition 
	
	//read numbers
	cout<<"Enter first number: ";
	cin>>a;
	cout<<"Enter second number: ";
	cin>>b;
	
	//call function
	add=addition(a,b);
	
	//print addition
	cout<<"Addition is: "<<add<<endl;
	
	return 0;
}

//function definition
int addition(int a,int b)
{
	return (a+b);
}

Example 4: sum of two numbers c++

#include<iostream>
using namespace std;
int main()
{
	double number1,number2;
  	double sum0;
  	sum=number1+number2;
  	cout<<sum;
}