Structures as Function Arguments

1. A function can have call-by-value and/or call-by-reference parameters of a structure type.
   
   
2. //Program to demonstrate the CDAccount structure type.
   //The example also includes a function that has a call-by-reference parameter
   //with the structure type CDAccount
   #include <iostream>
   
   //Structure for a bank certificate of deposit:
   struct CDAccount
   {
       double balance;
       double interest_rate;
       int term;   //months until maturity
   };
   
   
   void get_data(CDAccount& the_account);
   //Precondition: the_account must have been declared.
   //Postcondition: the_account.balance and the_account.interest_rate
   //have been given values that the user entered at the keyboard.
   
   int main( )
   {
       CDAccount account;
       get_data(account);
   
       double rate_fraction, interest;
       rate_fraction = account.interest_rate/100.0;
       interest = account.balance*rate_fraction*(account.term/12.0);
       account.balance = account.balance + interest;
   
       cout.setf(ios::fixed);
       cout.setf(ios::showpoint);
       cout.precision(2);
       cout << "When your CD matures in "
          << account.term << " months,\n"
          << "it will have a balance of $"
          << account.balance << endl;
       return 0;
   }
   
   //Uses iostream.
   void get_data(CDAccount& the_account)
   {
       cout << "Enter account balance: $";
       cin >> the_account.balance;
       cout << "Enter account interest rate: ";
       cin >> the_account.interest_rate;
       cout << "Enter the number of months until maturity: "
       cin >> the_account.term;
   }
   
   
3. A structure type can also be the type for the value returned by a function. Consider for example the following function definition:
   
   CDAccount shrink_wrap(double the_balance, double the_rate, int the_term)
   {
      CDAccount temp;
      temp.balance = the_balance;
      temp.interest_rate = the_rate;
      temp.term = the_term;
      return temp; }
   
   Once the shrink_wrap function is defined, a value can be given to a variable of type CDAccount as shown below:
   
   CDAccount new_account;
   new_account = shrink_wrap(1000.00, 5.1, 11);
   
   
4. Hierarchical structure can be used. That means that a structure can have member variables that are also structures.
   
   For example if we have a structure to represent the date:
   
   struct Date
   {
      int month;
      int day;
      int year;
   };
   
   We can use it in the definition of another structure PersonInfo:
   
   struct PersonInfo
   {
      char sex;
      double height;
      int weight;
      Date birthday;
   };
   
   So if a structure of type PersonInfo is declared:
   
   PersonInfo person1;
   
   The year the person was born can be output to the screen as follows:
   
   cout << person1.birthday.year;