Returning Operator to Switch Statement

[basanta]

oper is an integer, so the cin will fail if the user enters valid input. Use a char instead. Also, you are asking the user to enter the operator twice.
Furthermore:
- Why do you have a global variable 'c'?
- Keep input/output out of classes that have nothing to do with it. Your fraction class should not have functions that use input/output. Either overload the stream operators or use some global functions.
- Your classes are not const-correct.
- Your operators are not implemented correctly.

I used global variable for input where user input int/int in console screen and 'c' is for user choice like 2/5 or 2:5..
Const-correct? Pardon. It mean, my classes are not constant?
Yah, i am pretty much sure, my operator are not implemented correctly, but, i am confused how to implement it..

Can you help me ?
Regards
Basanta