C++3

1，函数与指针

#include<iostream>

using namespace std;

int Sum (int *pa,int nLen);

void main()

{

int  arr[]={1,2,3,4,5,6,7,8,9,010};

cout<<Sum(arr,10)<<endl;

}

int Sum(int *pa,int nLen)

{

int nRet=0;

for(int i=0;i<nLen;i++)

{

nRen+=pa[i];

}

return nRent;

}

在指针函数中的不到局部变量的值，只能得到地址，因为不能指向局部变量。

int *a();

int * b();

int i;

void main()

{

int *c=a();

cout<<*c<endl;//10

int *d=b();

cout<<*d<<endl;//7673859地址

}

int *a(){

{int i=10;

return i;

}

int *b(){

{

int j=20;

return j;

}

3，利用函数指针调用函数

#include<iostream>

using namespace std;

int Sum(int *pArr,int nLen);

void DispMsp(char *pMsg);

int (*fp1)(int *pArr,int nLen);

void (*fp2)(char *pMsg);

float (*fp3)(int *pArr,int nLen);

void main(){

fp1=Sum;

fp2=DispMsg;

int arr[]={1,2,3,4,5,6,7,8,9,10}

fp2("wwwwwwwwwwww");

(*fp2)("ddddddddddddd");

int nRet=fp1(arr,10);

cout<<nRet<<endl;

int Sum (int *pArr,int nLen){

int nRet=0;

for(int i=0;i<nLen;i++)

{

nRet+=pArr[i];

}

return nRent;

}

void Dispmsg(char*pMsg)

{

cout<<pMsg<<endl;

}

4,函数的缺省参数

#includ<iostream>

using namespace std;

void main()

{int i;

int nSum=0;

for(i=1;i<=num;;i++)

{

nSum+=i;

}

cout<<nSum<<endl;

}

void main()

{sum(100);

sum();

}

5,函数重载

int a(int b)

{

return a;

}

float a(float b)

{return b}

 

void main(){

int a=10;

float b=10.123;

cout<<a(a)<<endl;

cout<<b(b)<<endl;

}

6嵌套调用

fun1(int a,int b){

float v;

v=fun2(b-1,b+1);

}

fun2(int a,int b){

{}

递归调用

long fact(long n){

if(n==1)

return 1;

return fact(n-1)*n;

}

1，结构的定义

struct 结构名

{数据类型  成员名1；

数据类型  成员名2；

数据类型  成员名3；

。。。。}

1.2使用结构

#includes<iostream>

#include <string>

using namespace std;

struct Student

{

int nID;

char szName[20];

char szAddr[100];

char szPhone[15];

float fScore;

};

void main()

{

Student s;

s.nId=1;

strcpy(s.szName,"www");

strcpy(s.szAddr,"qqq");

strcpy(s.szPhone"3434");

s.fScore=93.5;

cout<<s.nID<<endl;

cout<<s.sxzName<<endl;

cout<<s.szAddr<<endl;

cout<<s.szPhone<<endl;

cout<<s.fSore<<endl;

}

1.3结构与指针

#includes<iostream>

#include <string>

using namespace std;

struct Student

{

int nID;

char szName[20];

char szAddr[100];

char szPhone[15];

float fScore;

};

void main()

{

Student s;

Student *ps;

ps=&s;

ps->nID=1;

strcpy(ps->szName,"liming");

>>>>>>

cout<<ps->nId<<endl;

。。。。。

}

1.4结构和数组

#includes<iostream>

#include <string>

using namespace std;

struct Student

{

int nID;

char szName[20];

char szAddr[100];

char szPhone[15];

float fScore;

};

void main()

{Student S[5]={{1,"lingmi",1988,"rrtew","4646",98.3},

                         {.............}........

                         }

cout<<s[i].nID<<endl;

........}

1.5结构和函数

2，枚举

#include<iostream>

#include<string>

using namespace std;

enum WEEKDAY{SUN=0,MON,TUE,WED,THU,FRI,SAT};

void PrintInfo(WEEKDAY Day);

void main()

[
WEEKDAY DAY=MON;

PrintInfo(day);

}

void PrintInfo(KEEKDAY DAY)

{

switch(day)

{case MON:

cout<<"今天是星期一"<<endl;

braek;

case .........

........}

3.用typedef声明类型

typedef struct tagStudent

{

int nID;

...........

..............

}