运行的时候，系统找不到指定的文件

这是源码：
#include
using namespace std;
class Box
{
public:
double length;
double breadth;
double height;
//成员函数声明
void set(double len,double bre,double hei);
double get();
};
//成员函数定义
void Box::set(double len,double bre,double hei)
{
length = len;
breadth = bre;
height = hei;
}
double Box::get()
{
return length * breadth * height;
}

int mian()
{
Box box1;
Box box2;
Box box3;
double volume = 0.0;
box1.set(5.0, 6.0, 7.0);
box2.set(10.0, 12.0, 13.0);
box3.length = 16.0;
box3.breadth = 8.0;
box3.height = 12.0;
volume = box1.get();
cout << "box1的体积为：" << volume << endl;
volume = box2.get();
cout << "box2的体积为：" << volume << endl;
volume = box3.length * box3.breadth * box3.height;
cout << "box3的体积为：" << volume << endl;

system("pause");
return 0;

}

你把main写成mian了

int main()