C++进阶STL-1
目录
第一章
函数模板基本语法
//模板技术 类型参数化 编写代码可以忽略类型
//为了让编译器区分是普通函数还是模板函数
template<class T>
void MySwap(T& a,T& b){
T temp = a;
a = b;
b = temp;
}
void test01(){
int a = 10;
int b = 20;
//1 自动类型推导
cout<<"a:"<<a<<"b:"<<b<<endl;
MySwap(a,b);
cout<<"a:"<<a<<"b:"<<b<<endl;
double da = 1.13;
double db = 1.14;
cout<<"da:"<<da<<"db:"<<db<<endl;
MySwap(da,db);
cout<<"da:"<<da<<"db:"<<db<<endl;
}
//2 显式的指定类型
MySwap<int>(a,b); 函数模板和普通函数的区别
函数模板不能进行自动类型转换，普通函数可以。
类模板
template<class T>
class Person{
public:
Person(T id, T age){
this->mAge = age;
this->mId = id;
}
void Show(){
cout<<"ID:"<<mId<<"Age:"<<mAge<<endl;
}
public:
T mId;
T mAge;
};
void test01(){
//函数模板在调用的时候，可以自动类型推导
//类模板必须显式指定类型
Person<int> p(10,20);
p.Show();
}
int main(){
return 0;
}类模板类内实现
类模板类外实现
#include<iostream>
using namespace std;
template<class T>
class Person{
public:
Person(T age,T id){
this->mID = id;
this->mAge = age;
}
void Show(){
cout<<"Age:"<<mAge<<"ID:"<<mID<<endl;
}
public:
T mAge;
T mID;
};
template<class T>
Person<T>::Person(T age,T id){
this->mID = id;
this->mAge = age;
}
template<class T>
void Person<T>:Show(){
cout<<"Age:"<<mAge<<"ID:"<<mID<<endl;
}
void test01(){
Person<int> p(10,20);
p.Show();
}
int main(void){
test01();
return 0;
}
第二章
MyArray框架搭建及实现
#include<iostream>
using namespace std;
template<class T>
class MyArray{
public:
MyArray(int capacity){
this->mCapacity = capacity;
this->mSize = 0;
//申请内存
this->pAddr = new T[this->capacity];
}
MyArray(const MyArray<T>& arr){
this->mSize = arr.mSize;
this->mCapacity = arr.mCapacity;
//申请内存空间
this=>pAddr = new T[this->mCapacity];
for(int i = 0; i < this->mSize; i++){
this->pAddr[i] = arr.pAddr[i];
}
}
T& operator[](int index){
return this->pAddr[index];
}
MyArray<T> operator=(const MyArray<T>& arr){
if(this->pAddr != NULL){
delete[] this->pAddr;
}
this->mSize = arr.mSize;
this->mCapacity = arr.mCapacity;
//申请内存空间
this=>pAddr = new T[this->mCapacity];
for(int i = 0; i < this->mSize; i++){
this->pAddr[i] = arr.pAddr[i];
}
return *this;
}
void PushBack(T& data){
if(this->mSize >= this->cmCapacity){
return;
}
this->pAddr[this->mSize] = data;
//mSize++
this->mSize++;
}
//对右值取引用
void PushBack(T&& data){
if(this->mSize >= this->cmCapacity){
return;
}
this->pAddr[this->mSize] = data;
//mSize++
this->mSize++;
}
MyArray(){
if(this->pAddr != NULL){
delete[] this->pAddr;
}
}
}
public:
int mCapacity;//一共可以容下多少个元素
int mSize;//当前数组有多少个元素
T* pAddr;//保存数据的首地址
}
void test01(){
MyArray<int> marray(20);
int a=10,b=20,c=30,d=40;
marray.PushBack(a);
marray.PushBack(b);
marray.PushBack(c);
marray.PushBack(d);
for(int i=0;i<marray.mSize;i++){
cout<<marray[i]<<" ";
}
cout<<endl;
}类型转换
static_cast
int a=97;
char c = static_cast<char>(a);
cout<<c<<endl;//基础数据类型指针
//int* p = NULL;
//char* sp = static_cast<char*>(p);
//对象指针
//Building* building = NULL;
//Animal* ani = static_cast<Animal*>(building);
//转换具有继承关系的对象指针
//父类指针转换为子类指针
//Animal* ani = NULL;
Cat* cat = static_cast<Cat*>(ani);
//子类指针转成父类指针
Cat* soncat = NULL;
Animal* anifather = static_cast<Animal*>(soncat);
Animal aniobj;
Animal& aniref = aniobj;
Cat& cat = static_cast<Cat&>(anief);
Cat catobj;
Cat& catref = catobj;
Animal& anifather2 = static_cast<Animal&>(catref);
//static_cast用于内置的数据类型
//还有具有继承关系的指针或引用//dynamic_cast 转换具有继承关系的指针或引用，在转换前会进行对象类型检查
//继承类型不能转换
//int a = 10;
/char c = dynamic_cast<char>(a);
//非继承关系的指针
//Animal* ani = NULL;
//Building* building = dynamic_cast<Building*>(ani);
//具有继承关系指针
//Animal* ani = NULL;
//Cat* cat = dynamic_cast<Cat*>(ani);
//报错是因为dynamic会做类型安全检查，子类比父类大
//Cat* cat = NULL;
//Animal* ani = dynamic_cast<Animal*>(cat);
//结论：dynamic只能转换具有继承关系的指针或引用
//只能从子类型转成基类型。//const_cast 指针 引用或对象指针
//基础数据类型
//int a = 10;
//const int& b = a;
//b = 10;//b不能修改
//int& c = const_cast<int&>(b);
//c = 20;
//看指针
const int* p = NULL;
int* p2 = const_cast<int*>(p);
int* p3 = NULL;
const int* p4 = const_cast<const int*>(p3);
//增加或去除变量的const性//reinterpret_cast 强制类型转换 无关的指针类型，包括函数指针可以
typedef void(*FUNC1)(int,int);
typedef void(*FUNC2)(int,char*);
void test04(){
//1、无关的指针类型都可以进行转换
Building* building = NULL;
Animal* ani = reinterpret_cast<Animal*>(building)
//2、函数指针转换
FUNC1 func1;
FUNC2 func2 = reinterpret_cast<FUNC2>(func1);
}总结：程序员必须清楚地知道要转换的变量，转换前是什么类型，转换后是什么类型，以及转换后有什么后果。一般情况下不建议进行转换，避免进行类型转换。
异常接口声明
void func() throw(int,float,char){
throw "abc";
}
//不能抛出任何异常
void func02() throw(){
throw -1;
}
//可以抛出任何类型异常
void func03(){
}第三章
文本文件操作
#include<iostream>
using namespace std;
#include<fstream>//文件读写
//文本文件读写
void test01(){
char* fileName = "C:\\Users\\apple\\Desktop\\sourse.txt";
char* fileName = "C:\\Users\\apple\\Desktop\\tarhet.txt";
ifstream ism(fileName,ios::in); //只读方式打开文件
ofstream osm(targetName,ios::out);
//ifstream ism;
//ism.open(fileName,ios::in);
if(!ism){
cout<<"打开文件失败!"<<endl;
}
//读文件
char ch;
while(ism.get(ch)){
cout<<ch;
osm.put(ch);
}
//关闭文件
ism.close();
osm.close();
}
