C++ STL for_each的应用

C++ STL for_each的使用
试定义类Complex和类ComplexAdd，使得下面main函数的执行结果为：

(3,5)

(5,7)

(7,9)

(9,11)

(11,13)

(6,8)

(8,10)

(10,12)

(12,14)

(14,16)

int main(void)

{
Complex A[] = { Complex(1, 2), Complex(3, 4), Complex(5, 6), Complex(7, 8), Complex(9, 10)};
vector<Complex> aa(A, A + 5);
for_each(aa.begin(), aa.end(), ComplexAdd(2,3));
for_each(A, A+10, ComplexAdd(5,6));
vector<Complex>::iterator p;
for ( p = aa.begin(); p != aa.end(); p++)
cout << *p;
cout << endl;
int i;
for (i = 0; i < 5; i++)
cout << A[i];
return 0;
}
下面是我写的：
class Complex{
int rec;
int vir;
public:
Complex(int r=0,int v=0){
rec=r;vir=v;
}
friend ostream&operator<<(ostream &os,const Complex&com);
friend class ComplexAdd;
};

ostream&operator<<(ostream&os,const Complex&com){
os<<"("<<com.rec<<","<<com.vir<<")"<<endl;
return os;
}

class ComplexAdd{
Complex com;
public:
ComplexAdd(int a,int b){
com.rec+=a;com.vir+=b;
}
};
编译的时候出现问题：
项不会计算为接受1个参数的函数
错误指向for_each函数的源代码

------解决方案--------------------
for_each(aa.begin(), aa.end(), ComplexAdd(2,3));

Complex对象没复制给ComplexAdd里面的com啊。。。
------解决方案--------------------
函数对象不是这么用的
应该重载()运算符，然后直接在for_each里调默认构造的ComplexAdd就行了
------解决方案--------------------

C/C++ code

#include <iostream>
#include <algorithm>
#include <vector>

class Complex
{
public:
    Complex(int x,int y)
    :_x(x),_y(y){
    }
    ~Complex()
    {
    }
    void setX(int x)
    {
        _x = x;
    }
    void setY(int y)
    {
        _y = y;
    }
    int getX()const
    {
        return _x;
    }
    int getY()const
    {
        return _y;
    }
private:
    int _x,_y;
};

std::ostream & operator<<(std::ostream & os,const Complex &c)
{
    os<<"("<<c.getX()<<","<<c.getY()<<")"<<std::endl;
    return os;
}

class ComplexAdd
{
public:
    ComplexAdd(int x,int y)
    :_x(x),_y(y)
    {
    }
    ~ComplexAdd()
    {
    }
    void operator()(Complex &c)
    {
        c.setX(c.getX()+_x);
        c.setY(c.getY()+_y);
    }
private:
    int _x,_y;        
};

int main(int argc,char *argv[])
{
    Complex A[]=
    {
        Complex(1,2),Complex(3,4),Complex(5,6),Complex(7,8),Complex(9,10)
    };
    std::vector<Complex> aa(A,A+5);
    std::for_each(aa.begin(),aa.end(),ComplexAdd(2,3));
    std::for_each(A,A+5,ComplexAdd(5,6));
    std::vector<Complex>::iterator p;
    for(p = aa.begin();p!=aa.end();p++)
    {
        std::cout<<*p;
    }
    std::cout<<std::endl;
    int i;
    for(i = 0; i < 5;i++)
    {
        std::cout<<A[i];
    }
    return 0;
}

------解决方案--------------------

C/C++ code


class ComplexAdd{
Complex com;
public:
ComplexAdd(int a,int b){
com.rec+=a;com.vir+=b;
}

operator Complex() const 
{
  return com;
}

void operator()(Complex const& c)
{
   com.rec += c.rec;
   com.vir += c.vir;
}
};


ComplexAdd sum = std::for_each(v.begin(), v.end(), ComplexAdd(2,3));
Complex c = sum;
std::cout << "sum: " << c << std::endl;

C++ STL for_each的应用

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