#include<iostream>
#include<string>
using namespace std;
enum place{home,office,fax,cell,pager};
class Phone
{
private:
    int cc;
    int ac;
    int num;
    place type;
public:
    Phone(int c=0,int a=0, int n=0, place t=(place) 0):cc(c),ac(a),num(n),type(t){}
    void set();
    void print();
    friend void find(Phone &, int );
};

/*Phone :: Phone
{    cc=0;
    ac=0;
    num=0;
    type=(place)0;
}
*/
void Phone:: set()
{
    int i;
    cout<<"Please enter the phone number (Country code Area code Phone number and Type)"<<endl;
    cin>>cc>>ac>>num>>i;
    type=(place) i;
}

void Phone:: print()
{
    cout<<"Country code"<<'\t'<<"Area code"<<'\t'<<"Phone number"<<'\t'<<"Type"<<endl;
    cout<<cc<<'\t'<<ac<<'\t'<<num<<'\t';
    switch(type)
    {
    case 0: cout<<"Home"<<endl;
    case 1: cout<<"Office"<<endl;
    case 2: cout<<"Fax"<<endl;
    case 3: cout<<"Cell"<<endl;
    case 4: cout<<"Pager"<<endl;
    default:cout<<"Type Wrong"<<endl;
    }


}

void find( Phone &p ,int num)
{
    int i,j=0;
    for(i=0;i<3;i++)
    {
        if(p[i].num == num)
        {
            cout<<"Found the same number"<<endl;
            p[i].print();
            j=1;
            break;
        }
    }
   
   if(!j) cout<<"No phone number match"<<endl;
}

int main()
{
    Phone  p[3]={Phone(),Phone(),Phone()};
    int i,num
    for(i=1;i<3;i++)
    {
        p[i].set();
        p[i].print();
    }
    cout<<"Input the number you want to find"<<endl;
    cin>>num;
    find(p,num);
    return 0;
}
本程序主要的功能是输入电话号码（其中有区号还有类型），可以进行查询与更改。
我运用的是数组，但是为什么说我 if(p[i].num == num) 这句话有问题，有没有哪位高手能帮我一下啊？数组在类中是这样用的吧，还有存在一些原则性的错误？

这个问题自己解决了，但是又有新问题出现了
class Phone
{
private:
    。。。
public:
   。。。。
    friend void equal(Phone p[]);
};

void equal(Phone p[])
{
    int i,j=0;
    for(i=0;i<3;i++)
    {
        if(p[i].num==p[i+1].num)
        {
            cout<<"Equal number"<<endl;
            j=1;
            p[i].print();
        }
    }
    if(!j) cout<<"There is no equal phone number"<<endl;
}
int main()
{
    Phone  p[4]={Phone(),Phone(12345678,(place) 2),Phone(),Phone()};
    int i,num;
    p[0].print();
    p[1].print();
    for(i=2;i<4;i++)
    {
        p[i].set();
        p[i].print();
    }
    equal(p);
    cout<<"Input the number you want to find"<<endl;
    cin>>num;
    find(p,num);
    return 0;
}
又做了些改动（其他和原来的都一样），但是现在说我的equal函数出问题的了 if(p[i].num==p[i+1].num) ？这个为什么

#include<iostream>
#include<string>
using namespace std;
enum place{home,office,fax,cell,pager};
class Phone
{
private:
    int cc;
    int ac;
    int num;
    place type;
public:
    Phone(int c=0,int a=0, int n=0, place t=(place) 0):cc(c),ac(a),num(n),type(t){}
    void set();
    void print();
    friend void equal(Phone p[]);
};

/*Phone :: Phone
{    cc=0;
    ac=0;
    num=0;
    type=(place)0;
}
*/
void Phone:: set()
{
    int i;
    cout<<"Please enter the phone number (Country code Area code Phone number and Type)"<<endl;
    cin>>cc>>ac>>num>>i;
    type=(place) i;
}

void Phone:: print()
{
    cout<<"Country code"<<'\t'<<"Area code"<<'\t'<<"Phone number"<<'\t'<<"Type"<<endl;
    cout<<cc<<'\t'<<ac<<'\t'<<num<<'\t';
    switch(type)
    {
    case 0: cout<<"Home"<<endl;
    case 1: cout<<"Office"<<endl;
    case 2: cout<<"Fax"<<endl;
    case 3: cout<<"Cell"<<endl;
    case 4: cout<<"Pager"<<endl;
    default:cout<<"Type Wrong"<<endl;
    }


}

void equal(Phone p[])
{
    int i,j=0;
    for(i=0;i<3;i++)
    {
        if(p[i].num==p[i+1].num)
        {
            cout<<"Equal number"<<endl;
            j=1;
            p[i].print();
        }
    }
    if(!j) cout<<"There is no equal phone number"<<endl;
}

int main()
{
    Phone  p[3]={Phone(),Phone(),Phone()};
    int i,num;
    for(i=1;i<3;i++)
    {
        p[i].set();
        p[i].print();
    }
    cout<<"Input the number you want to find"<<endl;
    cin>>num;
    equal(p);
    return 0;
}

Phone &p改为Phone *p

//修改后程序如下
//修改部分已加红色

#include<iostream>
 #include<string>
 using namespace std;
 enum place{home,office,fax,cell,pager};
 class Phone
 {
 private:
     int cc;
     int ac;
     int num;
     place type;
 public:
     Phone(int c=0,int a=0, int n=0, place t=(place) 0):cc(c),ac(a),num(n),type(t){}
     void set();
     void print();
     friend void find(Phone [], int );    //引用传递不能用 p[i] 操作， 应改为指针，Phone *,或 Phone []
};
 
/*Phone :: Phone
 {    cc=0;
     ac=0;
     num=0;
     type=(place)0;
 }
 */
 void Phone:: set()
 {
     int i;
     cout<<"Please enter the phone number (Country code Area code Phone number and Type)"<<endl;
     cin>>cc>>ac>>num>>i;
     type=(place) i;
 }
 
void Phone:: print()
 {
     cout<<"Country code"<<'\t'<<"Area code"<<'\t'<<"Phone number"<<'\t'<<"Type"<<endl;
     cout<<cc<<"\t\t"<<ac<<"\t\t"<<num<<"\t\t";   //打印不对齐
     switch(type)
     {
     case 0: cout<<"Home"<<endl; break;   //少了 break；语句
     case 1: cout<<"Office"<<endl; break;
     case 2: cout<<"Fax"<<endl;   break;
     case 3: cout<<"Cell"<<endl;  break;
     case 4: cout<<"Pager"<<endl;  break;
     default:cout<<"Type Wrong"<<endl;
     }
 

}
 
void find( Phone p[] ,int num)  //引用传递不能用 p[i] 操作， 应改为指针，Phone *,或 Phone []
{
     int i,j=0;
     for(i=0;i<3;i++)
     {
         if( (p+i)->num == num)
        {
             cout<<"Found the same number"<<endl;
             p[i].print();
             j=1;
             break;
         }
     }
     
   if(!j) cout<<"No phone number match"<<endl;
 }
 
int main()
 {
     Phone  p[3]={Phone(),Phone(),Phone()};
     int i,num;             //缺少“;”(在“for”的前面)
     for(i=1;i<3;i++)
     {
         p[i].set();
         p[i].print();
     }
     cout<<"Input the number you want to find"<<endl;
     cin>>num;
     find(p,num);
     return 0;
 }
 

学习了

真是谢谢啊把我的问题解决了！