Day 1：Introduction


1.1 Why use a language like C++
 
Conciseness
Maintainability
Portability
1.2 The compilation process
         sorce file>>>Prcessed code>>>Object file
 
1.3 General notes on C++
 
             case sensitive
2.1 hello world
Cpp代码  
/*  
 * File:   main.cpp 
 * Author: Gong Li 
 * 
 * Created on June 24, 2011, 9:18 PM 
 */  
  
#include <iostream>  
  
using namespace std;  
  
/* 
 *  
 */  
int main() {  
    std::cout<<"Hello,world!";  
    return 0;  
}  
 
2.2 Tokens
            keywords, identifiers,literals, operators, punctuation, whitespace
 
2.3 Explaination
 
comment:           //.... or /*....*/
#include:           the preprocessor dumping in the content of another file.
int main(){}:     execute when the program starts up
cout <<:            outputting some piece of text
namespaces:    like std includes a group of idemntifiers
strings:             Hello, world!
escape sequence:   
...
return 0:           tell the OS it has completed successfully
 
3 Input
      Input  cin >> x
    
     Output cout << "hello"

补充：软件开发 , C语言 ,