完成程序，使其输出结果为x=30

#include "stdafx. h"

#include ﹤iostream﹥

using namespace std;

class Sample

{private:

intx;public:Sample( )

 {

Sample(int a)

 {

 x=a;

}

void disp( )

{

cout﹤﹤"x="﹤﹤x ﹤﹤ endl;

}

friend Sample operator+( Sample &s1, Sample &s2);

};

_________

Sample &s1,

 Sample &s2)

 {

returm Sample(s1. x +s2. x);

}

void main( )

 {

Sample obj1(10);

Sample obj2(20);

Sample obj3;

_________;obj3. disp( );

}

声明一个circle类，有数据成员Radius(半径, foat型)，成员函数GetArea( )计算圆的面积。在main函数中声明一个circle类的对象c1，其半径为5.6。调用 GetArea( )函数计算c1的面积，并显示该计算结果(cout﹤"圆的面积:"﹤﹤c1. Getarea﹤endl;)。

#include ﹤iostream.h﹥

using namespace std;

void main( )

{

int a[3][4]=

{

{1,2,7,8},{5,6,11,15},{9,20,3,7}

};

int m=a[0][0];

int i, j;

for(i=0; i﹤3; i++)

for(j=0; j﹤4; j++)

if(a[i][j]﹥m) m=a[i][j];

cout﹤﹤"m is:" ﹤﹤endl;

cout ﹤﹤m﹤﹤ endl;

}

#include ﹤ iostream.h﹥

using namespace std;

class example

{public:

example(int n)

 {

i=n;cout﹤﹤"Constructing";

}

~example( )

 {

cout ﹤﹤"Destructing";

}

int get_i( )

{

return i;

}

private:

int i;

};

int sqr_int( example o)

 {

retum o. get_i( )*o. get_i( );

}

void main( )

 {

example x(10);

cout ﹤﹤x. get_i( )﹤﹤ endl;

cout ﹤﹤ sqr_it(x)﹤﹤endl;

}

#include ﹤iostream﹥

#include ﹤fstream﹥

using namespace std;

void main( )

{

char *p="abcde";

_________myf("ab. txt");

myf ﹤﹤p;cout﹤﹤"this is a txt file";

_________;//关闭文件ab.txt

}

完成程序，使其输出结果为n=2,sum=2n=3,sum=5n=5,sum=10

#include ﹤iostream﹥

using namespace std;

class Sample

 {

int n;

static int sum;

public:

Sample(int x)

 {

n=x;

}

void add( )

{

_________;

}

void disp( )

 {

cout ﹤﹤"n="﹤﹤n﹤﹤"sum="﹤﹤sum﹤﹤end;

}

};

_________;

void main( )

 {

Sample a(2), b(3), c(5);

a. add( );

a. disp( );

b. add( );

b. disp( );

c. add( );

c. disp( );

}

#include ﹤iostream﹥

using namespace std;

class base

{

_________;

public:

base (int x, int y)

{

a=x, b=y;

 }

_________( base &p)

 {

cout ﹤﹤p. a ﹤﹤" "﹤﹤p. b﹤﹤ endl;

};

void main( )

{

base b(78, 87);b. show(b);

}

完成程序，使其输出结果为28

_________

using namespace std;

int a[8]={1,2,3,4,5,6,7};

void fun(int b[ ], int n);

void main( )

{

int m=8;fun(a, m);

cout ﹤﹤a[7]﹤﹤ endl;

}

void fun (int b[ ], int n)

 {

int i;for(_________)b[7]+=b[i];

}

完成程序，使其输出结果为x=30

#include "stdafx. h"

#include ﹤iostream﹥

using namespace std;

class Sample

{private:

intx;public:Sample( )

 {

Sample(int a)

 {

 x=a;

}

void disp( )

{

cout﹤﹤"x="﹤﹤x ﹤﹤ endl;

}

friend Sample operator+( Sample &s1, Sample &s2);

};

_________

Sample &s1,

 Sample &s2)

 {

returm Sample(s1. x +s2. x);

}

void main( )

 {

Sample obj1(10);

Sample obj2(20);

Sample obj3;

_________;obj3. disp( );

}

#include using namespace std;

class person

{

int x;public:void person( )

{

x=1;

 }

void set( int a)

 {

x=a;

}

void get( )

 {

cout ﹤﹤x﹤﹤ endl;

}

};

void main( )

{

person p;

p. set(6);

p. get( );

}

#include ﹤iostream﹥

using namespace std;

void main( )

{

int a[6]={1,2,3,4,5,6,7};

int i;for(i=0; i﹤7; i++)

cout ﹤﹤a[li] ﹤﹤ endl;

｝