const int LOW_END = 10;    // low end of incomes considered
const int HIGH_END = 100;  // high end of incomes considered
const int TABLE_SIZE = HIGH_END - LOW_END + 1;

typedef int tableType[TABLE_SIZE];

int Index(int Group)
// Returns the array index that corresponds to Group number.
{
   return Group - LOW_END;
}  // end Index

void ReadData(tableType IncomeData, int Low, int High)
// ---------------------------------------------------------
// Reads and organizes income statistics.
// Precondition: The calling module gives directions and
// prompts user. Input data is error-free and each input 
// line is in the form G N, where N is the number of 
// people with an income in the G-thousand-dollar group 
// and Low <= G <= High. An input line with values of zero 
// for both G and N terminates the input.
// Postcondition: IncomeData[G-Low] = total number of people
// with an income in the G-thousand-dollar group for each G 
// read. The values read are displayed.
// ---------------------------------------------------------
{
   int Group, Number;                        // input values

   for (Group = Low; Group <= High; ++Group) // clear array
      IncomeData[Index(Group)] = 0;

   for (cin >> Group >> Number; 
        (Group != 0) || (Number != 0);
        cin >> Group >> Number)
   {  // Invariant: Group and Number are not both 0
      cout << "Income group " << Group << " contains "
           << Number << " people.\n";
      IncomeData[Index(Group)] += Number;
   }  // end for
}  // end ReadData