对于友元描述正确的是(　　)

声明复数类，Complex，该类中有两个私有变量real，image分别表示一个复数的实部和虚部。为Complex类添加适当的构造函数。并使用友元函数add实现复数加法。

#include ﹤iostream﹥

using namespace std;

class Complex

{

private:

double real, image;

public:

voidsetRI( double a, double b)

{

real=a;

image=b;

}

doublegetReal( )

{

return real;

}

doublegetImage( )

{

return image;

}

void print( ) {

if( image ﹥0)

cot﹤﹤"复数:"﹤﹤real﹤﹤"+"﹤﹤ image﹤﹤"i"﹤﹤endl;

if( image ﹤0)

cout ﹤﹤"复数: "﹤﹤ real ﹤﹤"-"﹤﹤ image ﹤﹤"i"﹤﹤endl;

}

friend Complex add( Complex, Complex); //声明友元函数

};

void main( )

{

Complex c1(19, 0.864), c2, c3;

c2.setRI(90,125.012);

c3=ad(c1,c2);

cout﹤﹤"复数一:"; c1.pint( );

cout﹤﹤"复数二:"; c2. print( );

cout﹤﹤"相加后:"; c3.pint( );

}

写出程序运行结果

#include ﹤iostream.h﹥

int func(int a)

{

int b=0;

static int c =4;

b++; c--;

return(a+b+c);

 }

void main( )

{

int a =2;

for( int j=0; j ﹤2; j++)

cout ﹤﹤ func(a +j)﹤﹤" ";

}

请完成一下程序，使其输出结果为：　　x=5,y=27　　X=10,y=27

#include ﹤iostream﹥

using namespace std;

class Sample

{ private:

int x;

static int y;

_____①_____:

Sample( int a);

void print( );

};

Sample:: Sample(int a)

{　　x=a;　　y++;　　}

void Sample:: print( )

{

cout﹤﹤"x="﹤﹤x﹤﹤",y="﹤﹤y﹤﹤ endl;

}

_____②_____

void main( )

{

Sample s1(5);

Sample s2(10)

s1. print( );

s2. print( );

}

写出程序运行结果

#include "stdafx. h"

#include ﹤iostream﹥

using namespace std;

class B;class A

{ public:

A(int i) { a=i; }

friend int F(A &f1, B &f2);

private:

int a;

};

class B

{ public:

B(int i) { b=i; }

friend int F(A &f1, B &f2);

private:

int b;

};

int F(a &f1, B &f2)

{ return(f1. a+f2. b)*(f1. a-f2.b); }

void main( )

{

A n1(10);

B n2(8)

cout﹤﹤F(n1, n2)﹤﹤endl;

 }

在下列程序的空格处填上适当的字句，使输出为：0，2，10。

#include "stdafx. h"

#include ﹤iostream﹥

#include "math. h"

using namespace std;

class Magic

{ double x;

public:

Magic( double d=0. 00): x(fabs(d))　　{ }

Magic operator+( _____①_____ )

{

return Magic(sqrt(x*x+c.x*c.x));

}

_____②_____﹤﹤(ostream & stream, Magic &c)

{ stream ﹤﹤c. x;　　return stream;　　}

};

void main( )

{

Magic ma;

cout﹤﹤ma﹤﹤","﹤﹤ Magic(2)﹤﹤","﹤﹤ma+Magic(-6)+Magic(-8)﹤﹤endl;

}

下面是一个输入半径，输出其面积和周长的C++程序，在下划线处填上正确的语句。

#include "stdafx. h"

#include ﹤iostream﹥

#include "math. h"

_____①_____

_____②_____

void main( )

{

double rad;

cout ﹤﹤"rad=";

cin﹥﹥rad;

double l=2.0*pi*rad;

double s= pi*rad*rad;

cout ﹤﹤"\n The long is: "﹤﹤l﹤﹤endl;

cout ﹤﹤"The area is: "﹤﹤s﹤﹤endl;

}

在下面程序横线处填上适当字句，以使该程序执行结果为：　　50 4 34 21 10　　6.1 7.1 8.1 9.1 10.1 11.1

#include ﹤iostream﹥

using namespace std;

template ﹤class T﹥

void f( _____①_____ )

{ _____②_____

for(int i=0; i﹤n/2; i++)

t=a[i], a[i]=a[n-1-i], a[n-1-i]=t;

}

void main( )

{ int a[5]={10,21,34,4,50};

double d[6]={11.1,10.1,9.1,8.1,7.1,6.1};

f(a,5); f(d,6);

for(int i=0; i﹤5; i++)

cout ﹤﹤ a[i]﹤﹤" ";

cout ﹤﹤ endl;

for(int i=0; i﹤6; i++)

cout﹤﹤d[i]﹤﹤" ";

cout﹤﹤ endl;

}

在下面程序的底藏线处填上适当的字句，使该程序执行结果为40，x为静态成员。

include ﹤iostream.h﹥

class Test

{ public:

_____①_____;

Test (int i=0)

{ x=i+x; }

int Getnum( )

{ returm Test:: x+10; }

};

_____②_____;

void main( )

{

Test test;

cout﹤﹤test. Getmum( )﹤﹤ endl;

}

#include "stdafx.h"

#include ﹤iostream﹥

using namespace std;

class A

{

 int i;

public:

virtual void fun( )=0;

A( int a)

{ i=a;}

};

class B: public A

{

 int j;

public:

void fun( )

{

cout﹤﹤"B:: fun( )\n";

}

B(int m, int n=0): A(m),j(n) { }

};

void main ( )

{

 A *pa;

B b(7);

pa=&b;

}

#include ﹤iostream. h﹥

#include ﹤string. h﹥

class Base

{ public:

Base( char *s="\0") { strcpy ( name, s); }

void show( );

protected:

char name[20];

};

Base b;

void show( )

{ cout ﹤﹤"name: "﹤﹤b. name ﹤ endl; }

void main( )

{

Base d2("hello");

show( );

}