c++初始化对象数组错误，望各路大神不吝赐教

class NU
{

private:

std::string nucname;
double activity_1;
double activity_2;
double activity_3;

public:

void factor1(const std::string & co, double act_class_1, double act_class_2, double act_class_3);

void show();

};
类声明如上

const int s = 4;

NU nuc_class[s] = { NU("Ba137",0,0,0),NUCLEAR("ZN 69M",0,0,0),NU("ZN 69M",0,0,0),NU("ZN 69M",0,0,0) };//生成10个类，此处生成4个

初学c++，简单创建了对象数组，结果vs编译显示无法从“initializer list”转换为“NU”
无构造函数可以接受源类型，或构造函数重载决策不明确

很疑惑，调试不出来，各路大神不吝赐教哇，谢谢！

在类中加入构造函数，对的类的成员变量进行初始化 NU（string nucname， double activity_1，double activity_2，double activity_3）{
this->nucname = nucname;
this->activity_1 = activity_1;
this->activity_2 = activity_2;
this->activity_3 = activity_3;
}

在头文件中添加NUCLEAR();

后在.cpp文件中添加构造函数，问题得以解决

NU::NU()
{
	nucname = "no name";
	activity_1 = 0.0;
	activity_2 = 0.0;
	activity_3 = 0.0;
	activity_4 = 0.0;
	activity_5 = 0.0;
	activity_6 = 0.0;
	activity_7 = 0.0;
	activity_8 = 0.0;
	activity_9 = 0.0;
	activity_10 = 0.0;
}

本人是新手，这一构造函数好理解些。大神的构造函数有空我再看看