填空题 阅读以下说明和C++程序，将应填入{{U}} (n) {{/U}}处的字句写在对应栏内。
[说明]
下面程序输出一个矩形面积，以及矩形区域上的假想的作物产量。
[C++程序]
#include ＜iostream.h＞
class crop_assessment
{
int actual_crop;
int ideal_crop;
public:
void set(int in_actual,int in_ideal)
{
actual crop=in_actual;
ideal_crop=in_ideal;
}
int get_actual_crop(void){{{U}} (1) {{/U}};}
int get_ideal_crop(void){{{U}} (2) {{/U}};)
};
Class lot_size
{
int length;
int width;
{{U}} (3) {{/U}} crop;
public:
void set(int 1,int w,int a,int i)
{
length=1;
width=w;
crop.set(a,i);
}
int get_area(void){return length^*width;}
int get_data(void){return{{U}} (4) {{/U}};}
int get_data2(void)freturn{{U}} (5) {{/U}};}
}
int main()
{
Los_size small，medium;
small.set(5,5,5,25);
medium.set(10,10,10,50);
cout＜＜"For a small lot of area"＜＜smallget_area()＜＜“/n”;
cout＜＜"the actual crops are$"＜＜small.get_data2()＜＜"/n";
cout＜＜"and ideal crops are$”＜＜small.get_data()＜＜"/n";
cout＜＜"For a medium Lot of area"＜＜medium.get area()＜＜:/n”;
cout＜＜"the actual crops are$"＜＜medium.get_data2()＜＜"/n";
cout＜＜"and ideal crops are$"＜＜medium.get_data()＜＜"/n";
return 0;
}