/*
   lab05.cpp
   CIS 150
   6/9/2005
   David Klick
   
   This program demonstrates the use of repetition structures
   in C++.
*/

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <ctime>
using std::cin;
using std::cout;
using std::ifstream;
using std::ofstream;

int main(void) {
   int i;      // loop counter
   int sum;    // accumulator for steps #4 and #5
   int num;    // holds random numbers (steps #7 and #8)
   
   // seed random number generator (for step #7)
   srand(time(NULL));
   
   // step 1 of lab exercise
   for (i=0; i<100; i+=7) {
      cout << i << " ";
   }
   cout << '\n';
   
   // step 2 of lab exercise
   i = 0;
   do {
      cout << i << " ";
      i += 7;
   } while (i <= 100);
   cout << '\n';
   
   // step 3 of lab exercise
   i = 0;
   while (i <= 100) {
      cout << i << " ";
      i += 7;
   }
   cout << '\n';

   // step 4 of lab exercise
   sum = 0;
   for (i=0; i<100; i+=7) {
      sum += i;
   }
   cout << "The sum of all multiples of 7 between 0 and 100 is "
        << sum << '\n';
        
   // step 5 of lab exercise
   sum = 0;
   do {
      cout << "Enter an integer (-999 to exit): ";
      cin >> num;
      if (num != -999) sum += num;
   } while (num != -999);
   cout << "The sum is " << sum << '\n';

   // step 6 of lab exercise
   for (i=1; i<=10; i++) {
      if (i%4==0) continue;
      cout << i << " ";
   }
   cout << '\n';

   // step 7 of lab exercise
   ofstream ofile("lab04.data");
   if (!ofile) {
      cout << "Error: Couldn't open output file!\n";
      return 1;
   }
   for (i=1; i<=10; i++) {
      num = rand() % 26 + 50;
      ofile << num << '\n';
   }
   ofile.close();
   
   // step 8 of lab exercise
   ifstream ifile("lab04.data");
   if (!ifile) {
      cout << "Error: Couldn't open input file!\n";
      return 2;
   }
   ifile >> num;  // priming read from file
   while (ifile) {  // continue if read worked
      cout << num << " ";
      ifile >> num;
   }
   ifile.close();

   return 0;
}

/*
   Sample output:
   
   0 7 14 21 28 35 42 49 56 63 70 77 84 91 98
   0 7 14 21 28 35 42 49 56 63 70 77 84 91 98
   0 7 14 21 28 35 42 49 56 63 70 77 84 91 98
   The sum of all multiples of 7 between 0 and 100 is 735
   Enter an integer (-999 to exit): 27
   Enter an integer (-999 to exit): 13
   Enter an integer (-999 to exit): -10
   Enter an integer (-999 to exit): -999
   The sum is 30
   1 2 3 5 6 7 9 10
   55 69 66 61 69 73 66 75 67 70
*/