PROGRAMMING:Implementation of cube class

The implementation of the cube class box, complete the calculation of volume, surface area, output results and other functions. The given main function is:
int main( ){
float ab;
cin>>ab;
Box obj;
obj.seta( ab );
obj.getvolume( );
obj.getarea( );
obj.disp( );
return 0;
}
###Input format:
The side length of the cube can be float type data.
###Output format:
The volume and surface area of the cube are separated by a space in the middle and wrapped at the end.
###Input example:
```in
three
```
###Output example:
```out
27 54
```






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