i want this function to not except characters but each time i enter it, it gives me a run time erro

how can i do it such that the function only ecepts yes no 1 and 0, but not any sort of character

please help me ( using c++)

string answery coutes" In nwould You Like To perform another Procedure? ? cinss answers if(Canswer"yes")|(answer"Yes")(answen"YES") return true; 3. coutes "It It NOTE I"Write Either [Yes P] To continue oR [No e] To Stopl" return confirm() P