[英]If a class contains object of another class can it be initialized by having default value in the constructor of containing class in C++?
編譯此代碼會產生錯誤
error time constructor time::time(int,int,char) cannot be overloaded with time::time(int,int,char)
我試圖減少重載的構造函數,所以我試圖在構造函數參數中提供默認值。 是行entry(int sno=5,time t{1,2,'p'});
在entry
類的構造函數中有效嗎? 如果一個類包含另一個類的復雜對象,那么它可以通過這種方式初始化嗎?
#include<iostream>
using namespace std;
class time
{
int hours;
int mins;
char ap;
public:
time(int hours=0,int mins=0,char ap='n');
time(int a, int b, char c): hours{a},mins{b},ap{c}
{
}
void showtime()
{
cout<<"\nTime : "<<hours<<" "<<mins<<" "<<ap<<endl;
}
};
class entry{
int sno;
time t;
public:
entry(int sno=5,time t{1,2,'p'});
void showdata()
{
cout<<"\ne : "<<sno<<" : ";
t.showtime();
}
};
int main()
{
entry e;
e.showdata();
return 0;
}
是的,這是可能的,這只是語法:
#include<iostream>
using namespace std;
class Time
{
int _hours;
int _mins;
char _ap;
public:
Time(int hours=0,int mins=0,char ap='n'): _hours(hours),_mins(mins),_ap(ap)
{};
void showtime()
{
cout<<"\nTime : "<< _hours << " " << _mins << " " << _ap << endl;
}
};
class entry{
int _sno;
Time _t;
public:
entry(int sno=5,Time t = Time(1,2,'p')):
_t(t), _sno(sno)
{};
void showdata()
{
cout<<"\ne : "<< _sno<<" : ";
_t.showtime();
}
};
int main()
{
entry e;
e.showdata();
Time t2(5,2,'a');
entry e2(3, t2);
e2.showdata();
return 0;
}
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