// Fig. 2.5: ex2.05.cpp
// Text-printing program
#include <iostream>  // allow program to output data to the screen

// function main gegins program execution
int main() 
{	
	int number1; // first integer to add  declare(宣告)一個整數integer 叫做 number1  對應到的是分配一塊記憶體(memory)給這個variable(變數) 
	int number2; // second
	int sum;  // sum of number 1 and number 2;

	std::cout << "Enter first integer: ";
	std::cin >> number1;        // std::cin 會把 標準輸入(在這裡是鍵盤)的內容放到為number1分配的記憶體   >> 會把左邊的資料傳至右邊
	std::cout << "number1 is: ";
	std::cout << number1;   //將 number1記憶體內容輸出至表準輸出(即螢幕)
	std::cout << "\n";  

	std::cout << "Enter second integer: ";
	std::cin >> number2;
	std::cout << "number2 is: " << number2 << "\n";

	sum = number1 + number2;  \\ 為number1分配的記憶體 的內容  與 為number2分配的記憶體 的內容  相加  然後將結果放到為 sum 分配的記憶體
	std::cout << "the sum of number1 and number2 is: " << sum << std::endl;  // endl 等同 "\n"

	return 0;   // indicate that program end;ed successfully
}  // end of main function