Day 一：Introduction

Day 1：Introduction
1.1 Why use a language like C++

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ConcisenessMaintainabilityPortability

1.2 The compilation process?? ? ? ? sorce file>>>Prcessed code>>>Object file

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1.3 General notes on C++

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?? ? ? ? ? ? case sensitive

2.1 hello world

/*  * 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;}

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2.2 Tokens

?? ? ? ? ? ?keywords, identifiers,literals, operators, punctuation, whitespace

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2.3 Explaination

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comment: ? ? ? ? ? //.... or /*....*/#include: ? ? ? ? ? the preprocessor dumping in the content of another file.int main(){}: ? ? execute when the program starts upcout <<: ? ? ? ? ? ?outputting some piece of textnamespaces: ? ?like std includes a group of idemntifiersstrings: ? ? ? ? ? ? Hello, world!escape sequence: \b ?\n...return 0: ? ? ? ? ? tell the OS it has completed successfully

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3 Input

?? ? ?Input ?cin >> x
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?? ? Output cout << "hello" ??
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