====hello world=====
＃i nclude "stdafx.h"

int main(int argc, char* argv[])
{
 printf("Hello World!\n");
 return 0;
}
====累加器====
＃i nclude "stdafx.h"
＃i nclude "iostream"
using namespace std;

int main()
{
    int ir=0;
  for(int i=1;i<=100;i++){
   ir+=1;
  }
 cout<<"value is "<<ir<<endl;
 return 0;
}

========布尔型变量=====
＃i nclude "stdafx.h"
＃i nclude "iostream"
using namespace std;

int main()
{
    bool t=true;
 cout<<t<<endl;
 t=false;
 cout<<t<<endl;
 return 0;
}

=======数组和指针方式定义字符串====
＃i nclude "stdafx.h"
＃i nclude "iostream"
using namespace std;

int main()
{
     char* str1="hi";
  char str2[]="hi,hi";
  cout<<str1<<endl<<str2<<endl; //原来*str1代表着指针所指向的字符串的第一个值
  return 0;
}
========判断字符串长度,构造了一个函数,用指针来移位.=====
＃i nclude "stdafx.h"
＃i nclude "iostream"
using namespace std;
int getleng(char* str){
 int lengstr=0;
 while(*str++){
  lengstr+=1;
 }
 return lengstr;
};
int main()
{
     char* msg="hello,world!";
  int lengstr2;
  lengstr2=getleng(msg);
  cout<<lengstr2<<endl;
  return 0;
};

========string 数据类型=======
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

int main()
{
     char* msg="hello,world!";
  string str1="aaa";
  string str2="bbb";

  string str3(msg);
  cout<<str1<<endl<<str3<<endl;
  return 0;
};
=========定义枚举类型,结合case=====
＃i nclude "stdafx.h"
＃i nclude "iostream"
using namespace std;

enum family_member{father=0,mother=1,xiaoming=3};
void print_mem(family_member member){
 switch(member) {
 case father:
  cout<<"oh,he is my fahter"<<endl;
  break;
 case mother:
  cout<<"oh,he is my mother"<<endl;
  break;
 case xiaoming:
  cout<<"oh,he is xiaoming"<<endl;
  break;
 default:
  cout<<"I dont know who he is"<<endl;
 }
}

int main()
{
 for (int i=0;i<4;i++) {
  print_mem((family_member) i);
     };
 return 0;
};
=========结构体的定义与使用=====
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

struct student {
 string Name;
 bool IsBoy;
 int age;
};

void printinfo(student s){
 cout<<"姓名:"<<s.Name<<endl;
 cout<<"年龄:"<<s.age<<endl;
 if (s.IsBoy) {
  cout<<"性别为男"<<endl;
  }
 else{
  cout<<"性别为女"<<endl;
 };
 
};
int main()
{
 student xiaoming;
  xiaoming.Name="小明";
  xiaoming.IsBoy=true;
  xiaoming.age=23;

 printinfo(xiaoming);
 return 0;
};
=====数组的定义,赋值,取长,计算
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

int main(){
 int m[]={1,2,3,4,5};
 int lengthm=sizeof(m)/sizeof(int); //数组的个数

 for (int i=0;i<lengthm;i++) {
  m[i]++;
 };

 for (i=0;i<lengthm;i++)
 {
  cout<<m[i]<<endl;
 }
 return 0;
}
====用指针来代表数组
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

int main(){
 int m[]={1,2,3,4,5};
 int lengthm=sizeof(m)/sizeof(int);

 int *p=m;
 for (int i=0;i<lengthm;i++)
 {
  cout<<*p<<endl; //如果p,则输入指针地址
  p++;            //*p++也可以
 }
 return 0;
}
======指针定义,取地址与占空间=
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

struct student {
 string Name;
 bool IsBoy;
 int age;
};
int main()
{
 student xiaoming;
  xiaoming.Name="小明";
  xiaoming.IsBoy=true;
  xiaoming.age=23;
student* pStu=0; //定义指针
pStu=&xiaoming;  //指向xiaoming的地址
int* pInt=0;
pInt=&xiaoming.age;
bool* pBool=0;
pBool=&xiaoming.IsBoy;
string* pString=0;
pString=&xiaoming.Name;

cout<<pStu<<endl;   //输入地址
cout<<pInt<<endl;
cout<<pBool<<endl;
cout<<pString<<endl;
cout<<"===="<<endl;
cout<<sizeof(pStu)<<endl;  //指针所占的空间是一样的.
cout<<sizeof(pInt)<<endl;
cout<<sizeof(pBool)<<endl;
cout<<sizeof(pString)<<endl;
cout<<"===="<<endl;
cout<<sizeof(*pStu)<<endl; //指针的值所占空间
cout<<sizeof(*pInt)<<endl;
cout<<sizeof(*pBool)<<endl;
cout<<sizeof(*pString)<<endl;
cout<<"===="<<endl;
cout<<sizeof(xiaoming)<<endl; ////指针的值所占空间
cout<<sizeof(xiaoming.age)<<endl;
cout<<sizeof(xiaoming.IsBoy)<<endl;
cout<<sizeof(xiaoming.Name)<<endl;
return 0;
};
========指针加====
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

int main()
{
int i=51;
int* p=&i;
cout<<i<<*p<<endl;
i++;
cout<<i<<endl;
i=*p+1;
cout<<i<<endl;
cout<<"==="<<endl;
i=*p+1;
cout<<*p<<endl;
return 0;
};
========获取类的静态成员=======
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

class M
{
public:
 static int i;
 static void print(int* ptr){
  if(ptr){
   cout<<*ptr<<endl;
  }
 }
};

int M::i=100;

int main()
{
 M::i++;
 M::print(&M::i);
 return 0;
};
======变量生效的范围
＃i nclude "stdafx.h"
＃i nclude "iostream"
＃i nclude "string"
using namespace std;

int i=9; //这个是全局的

void print(){
 int i=20; //这个是print里的
 cout<<i<<endl;
}

int main()
{
 int i=100;  //这个是main里的
 cout<<i<<endl;

 print();

 ::i++;
 cout<<::i<<endl;

 return 0;
};