Question

Define a function ValidRoom() that passes in a string parameter and returns true if the string parameter obeys all rules for a building's room address, else returns false. The rules are: (1) Must be two or three characters long. (2) First two characters must be digits, (3) If third character exists, must be a letter (upper or lowercase).
Examples of strings yielding true: "65", "00", "21L". Examples of strings yielding false: "356", "7", "A23", " 65", "45AB".

Recall some available character functions are: isalpha(), isdigit(), isspace(), toupper(), tolower().

(C++ Please!)

Answer 1

Code:

#include<iostream>
#include<string>
#include<ctype.h>

using namespace std;

//Function definition
bool ValidRoom(string room)
{
   int len =room.length();
  
   // checking that length must be two or three characters long
   if( len == 2 || len == 3 )
   {
       // Checking that first two characters must be digits
       if( isdigit(room[0]) && isdigit(room[1]) )
       {
           // Checking that if third character exists, must be a letter (upper or lowercase)
           if(len==3)
           {
               if(isalpha(room[2]))
                   return true;
               else
               return false;  
           }
           else
               return true;
       }
       else
           return false;
   }
   else
       return false;
}

// main method
int main()
{
   // An array of strings to test the function
   string arr[] = {"65", "00", "21L","356", "7", "A23", " 65", "45AB"};
  
   //Looping through the array and calling the ValidRoom method
   for(int i=0;i<8;i++)
   {
       // Displaying the result
       if(ValidRoom(arr[i]))
           cout<<arr[i]<<" is a valid room."<<endl;
       else
           cout<<arr[i]<<" is not a valid room."<<endl;
   }
  
   return 0;
}

Sample Run: