text: //
  //  pr_pset06_16:
  //
  //  Daphne invests $100 at 10% simple interest. (That is, every year,
  //  the investment earns an interest equal to 10% of the original investment.)
  //  Deirdre invests $100 at 5% interest compounded annually. (That is,
  //  interest is 5% of the current balance, including previous addition
  //  of interest.) Write a program that finds how many years it takes for
  //  the value of Deirdre’s investment to exceed the value of Daphne’s
  //  investment. Also show the two values at that time.
  //
  
  #include <stdio.h>
  
  #define INTEREST_SIMPLE     10.0
  #define INTEREST_COMPOUND   5.0
  #define INVESTMENT          100.0
  
  int main(void)
  {
      int years;
      double daphne, deidre;
      double dap_interest = INTEREST_SIMPLE;
      double deid_interest = INTEREST_COMPOUND;
  
      printf("Daphne invests $100 at 10%% simple interest.\n");
      printf("Deirdre invests $100 at 5%% interest compounded annually.\n");
  
      for (years = 1, daphne = deidre = INVESTMENT; deidre <= daphne; years++)
      {
          daphne = daphne + INVESTMENT * dap_interest / 100.0;
          deidre = deidre + deidre * deid_interest / 100.0;
          // printf("[%2d]: %7.2lf %7.2lf\n", years, daphne, deidre);
      }
      printf("After %d years Deidre exceeded Daphne \
  for the value of investments.\n", years);
      printf("Daphne: %.2lf\n", daphne);
      printf("Deidre: %.2lf\n", deidre);
  
      return 0;
  }
  