C++标准

标准的输入输出 
#include<iostream>
using namespace std;//打开命名空间 标准c++的组件都在std的标准库中  
输入 cin>>变量名   
输出 cout<<变量名 <<endl //endl输出换行并清除缓存
作用域 
#include<iosteam>
using namesapce std;
int a=200;
int main()
{ int a=100;
cout<<a<<endl;//输出的a为100//输出作用域最近的
}

若是想输出全局变量 a那么我们就该引入作用域运算符::  
::a代表全局变量 作用域运算符前面没有类名代表全局变量
定义命名空间 
namespace bird
{   int age=100;
}  
namesapce person
{
int age=200;
int main()
{
cout<<age<<endl;//这样输出就会报错因为程序并不知道是哪个age
}  
那么我们要输出age就有两种方法 1.打开命名空间  
using namespace bird;
using namespace person;
2.利用作用域运算符  cout<<bird::age<<endl;
c++是面向对象的语言 面性对象我们要考虑复用性和扩展性
动态的分配内存与释放
创建 int *p=new 要创建的数据类型;//在堆区动态分配空间
删除 delete p; p=0;//把p所指向的空间删除 p指针变量还在还装着原来的地址 要让p指向空;
分配一个整形数组
int *arr=new int [10]; 
delete [] arr; 
arr=0; 
int (*arr)[3]=new[2][3];
delete[]arr;
arr=0; 
定义函数
假如声明一个函数并给默认值 
void show(int a=10;int b=20;int c=30;int d=40) ;
在主函数中可以直接调用 也可以在主函数中重新赋值 若我们想附中间的值不赋两边的值就会出现问题
所以给函数的默认值是从后向前并且中间不能空
函数的重载 
同一个作用域 函数的名相同 函数的参数不同 
引用 
引用是c++语言的一种特殊的数据类型的描述 用于不同部分(作用域)两个及以上变量名指向同一块地址 
可以理解为变量的别名
int a; int &k=a;//k为a的引用也可以理解成a的别名 
引用只能认为是一个变量的别名 而指针可以指向任意一个空间 
指针和引用的区别
1.引用定义了就要初始化而指针不用
2.引用初始化后不能在重新引用其他空间
3.没有空的引用指针可以指向NULL  
函数参数的传递方式
1.值传递 2.地址传递 3.引用  
看是否修改传入的内容 修改不能用值传递 若不修改用值传递 
看是不是new的空间 是不是地址若是则用地址传递



该资源不适合C、C++初学者,可作为C++高手向大师级进化的参考书。 内容: ... 17 Library introduction 17.1 General 17.2 The C standard library 17.3 Definitions 17.4 Additional definitions 17.5 Method of description (Informative) 17.6 Library-wide requirements 18 Language support library 18.1 General 18.2 Types 18.3 Implementation properties 18.4 Integer types 18.5 Start and termination 18.6 Dynamic memory management CONTENTS v c ISO/IEC N3000=09-0190 18.7 Type identification 18.8 Exception handling 18.9 Initializer lists 18.10Other runtime support 19 Diagnostics library 456 19.1 General 19.2 Exception classes 19.3 Assertions 19.4 Error numbers 19.5 System error support 20 General utilities library 20.1 General 20.2 Requirements 20.3 Utility components 20.4 Compile-time rational arithmetic 20.5 Tuples 20.6 Metaprogramming and type traits 20.7 Function objects . 520 20.8 Memory 541 20.9 Time utilities 583 20.10Date and time functions 596 20.11Class type_index 596 21 Strings library 599 21.1 General 599 21.2 Character traits 599 21.3 String classes 605 21.4 Class template basic_string 608 21.5 Numeric Conversions 635 21.6 Null-terminated sequence utilities . 636 22 Localization library 640 22.1 General 640 22.2 Header <locale> synopsis 640 22.3 Locales 641 22.4 Standard locale categories . 653 22.5 Standard code conversion facets 693 22.6 C Library Locales 695 23 Containers library 696 23.1 General 696 23.2 Container requirements 696 23.3 Sequence containers 719 23.4 Associative containers . 758 23.5 Unordered associative containers . 776 24 Iterators library 791 24.1 General 791 24.2 Iterator requirements 791 CONTENTS vi c ISO/IEC N3000=09-0190 24.3 Header <iterator> synopsis 796 24.4 Iterator primitives 799 24.5 Iterator adaptors . 802 24.6 Stream iterators . 816 25 Algorithms library 825 25.1 General 825 25.2 Non-modifying sequence operations 835 25.3 Mutating sequence operations 839 25.4 Sorting and related operations 848 25.5 C library algorithms 862 26 Numerics library 864 26.1 General 864 26.2 Numeric type requirements . 864 26.3 The floating-point environment 865 26.4 Complex numbers 866 26.5 Random number generation . 876 26.6 Numeric arrays 920 26.7 Generalized numeric operations 940 26.8 C Library 944 27 Input/output library 949 27.1 General 949 27.2 Iostreams requirements . 950 27.3 Forward declarations 950 27.4 Standard iostream objects 952 27.5 Iostreams base classes . 954 27.6 Stream buffers 972 27.7 Formatting and manipulators 982 27.8 String-based streams 1009 27.9 File-based streams 1021 28 Regular expressions library 1036 28.1 General 1036 28.2 Definitions 1036 28.3 Requirements 1037 28.4 Header <regex> synopsis 1039 28.5 Namespace std::regex_constants 1045 28.6 Class regex_error 1048 28.7 Class template regex_traits 1048 28.8 Class template basic_regex 1051 28.9 Class template sub_match 1056 28.10Class template match_results 1062 28.11Regular expression algorithms 1066 28.12Regular expression Iterators . 1070 28.13Modified ECMAScript regular expression grammar 1076 29 Atomic operations library 1079 29.1 General 1079 29.2 Header <atomic> synopsis 1079 CONTENTS vii c ISO/IEC N3000=09-0190 29.3 Order and Consistency . 1082 29.4 Lock-free Property 1084 29.5 Atomic Types 1085 29.6 Operations on Atomic Types 1094 29.7 Flag Type and Operations 1098 29.8 Fences . 1099 30 Thread support library 1101 30.1 General 1101 30.2 Requirements 1101 30.3 Threads 1102 30.4 Mutual exclusion . 1107 30.5 Condition variables 1121 30.6 Futures 1129 A Grammar summary 1149 A.1 Keywords 1149 A.2 Lexical conventions 1149 A.3 Basic concepts 1154 A.4 Expressions . 1154 A.5 Statements . 1158 A.6 Declarations . 1159 A.7 Declarators . 1162 A.8 Classes . 1164 A.9 Derived classes 1165 A.10 Special member functions 1165 A.11 Overloading . 1165 A.12 Templates 1166 A.13 Exception handling 1167 A.14 Preprocessing directives 1167 B Implementation quantities 1169 C Compatibility 1171 C.1 C++ and ISO C 1171 C.2 Standard C library 1181 D Compatibility features 1185 D.1 Increment operator with bool operand . 1185 D.2 static keyword . 1185 D.3 Access declarations 1185 D.4 Implicit conversion from const strings . 1185 D.5 register keyword 1185 D.6 C standard library headers . 1185 D.7 Old iostreams members 1186 D.8 char* streams 1187 D.9 Binders 1196 D.10 auto_ptr 1198 E Cross references 1201 Index 1218 CONTENTS viii ISO/IEC N3000=09-0190 Index of Grammar Productions 1243 Index of Library Names 1246 Index of Implementation Defined Behavior 1280
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