```c++
#include<iostream.h>
void main()
{
int x=123;
double y=456.123;
cout<<"int所占字节"<<sizeof(int)<<endl;
cout<<"double所占字节"<<sizeof(double)<<endl;
}
```
```c++
#include<iostream.h>
void main()
{
int x=123;
double y=456.123;
cout<<"int所占字节"<<sizeof(int)<<endl;
cout<<"double所占字节"<<sizeof(double)<<endl;
}
```
命名空间没有引用吧。cout这些命令需要引用name space std。或者用std.cout