--> Frank Masingill wrote to Cliff Rhodes <--
FM>        Cliff, here is the program after I made the changes you
FM>suggested.  I do hope to develop it into a full-fledged C++ with
FM>some object-oriented features and I'm studying all of the examples
FM>I can find in my books and disks.  I started this as a project for
FM>the kids next door to play with when we keep them and wanted to get
FM>it to the point where they could play with it.
Frank, I think you are on the right track. I've looked at your updated 
version and most of the changes look good. It is still a C program, 
but that's OK at this point. I think you should continue on that line 
until you get it in top notch shape. Then do a conversion to C++.
The reason I say that is because going to C++ will require a different 
design approach. 
FM>I also had a message from Jerry Coffin with some suggestions
FM>along that line.
Yes, I saw it. Jerry suggested getting on a more solid C++ design 
basis. To me that might be a large jump from where you are. It might 
be better to go a little slower and evolve what you have into an OOP 
app. That's up to you.
I have taken your updated version and modified it. I reworked the 
xxxCalc() routines into one. You need to look at that and see if you 
can get the color exactly like you want it. I didn't do a good job on 
the color consistency after the answer is given.
Notice there are now no globals--so things are getting more polished.
// MATHPLAY.CPP 
// Edited 8/24/97
// Added Operation enum to help reduce all xxxCalc() routines into one
#include 
#include 
#include 
// Add this to give us some easy names for the calculations
enum Operation { Add = 0, Subtract, Multiply, Divide, NoOp };
int  menu(void);
int  calc(Operation op);
void promptc(int x, int y, int color , const char *p);
int main(void)
{
  while (menu())
    ;
  clrscr();
  promptc(1, 1, 11, "Thanks for playing!");
  return 0;
}
 
int menu()
{
   int i, col = 30;
   clrscr();
   promptc(col, 10, 14, "Would you like to practice a little");
   col=35;
   promptc(col, 12, 14, "1. Addition?");
   promptc(col, 13, 10, "2. Subtraction?");
   promptc(col, 14, 13, "3. Multiplication?");
   promptc(col, 15, 11, "4. Division?");
   promptc(col, 16, 12, "5. or just Quit?");
   do
   {
     promptc(col, 20, 15, "Enter your choice: ");
     scanf("%d", &i);
     switch(i)
     {
       case 1: calc(Add);      break;
       case 2: calc(Subtract); break;
       case 3: calc(Multiply); break;
       case 4: calc(Divide);   break;
       case 5: break;
     }
   }while (i  5);
   return (i == 5) ? 0 : 1;
}
int calc(Operation op)
{
   /* Performs the calculation type specified by the Operation.
    * Still lacks adequate input protection and checking!
    */
   
   /* Several arrays of labels follow. These assume that the
    * Operation Add has a value of 0, Subtract 1, etc. 
    */
   static const char *type[] = {
         "ADDITION", "SUBTRACTION", "MULTIPLICATION", "DIVISION" };
   static const char *arg1[] = {
         "first number (Addend)",
         "number to subract FROM (Minuend)",
         "number to be multiplied (MULTIPLICAND)",
         "number to be divided (DIVIDEND)"
   };
   static const char *arg2[] = {
         "second number (Addend)",
         "number to subract (Subtrahend)",
         "number to multiply it by (MULTIPLIER)",
         "number to divide it by (DIVISOR)"
   };
   static const char *ask[] = {
         "(called the SUM)",
         "(REMAINDER)",
         "(PRODUCT)",
         "(QUOTIENT)"
   };
   // A list of colors for each Operation type
   static const int colors[] = { 14, 10, 13, 11 };
   int num1, num2, guess, ans;
   if(op >= NoOp)   // Error, this should not happen
      return 1;
   do      // In case the user wants to do another problem, loop here
   {
      int col = 20;
      clrscr();
      gotoxy(col, 10);
      textcolor(colors[op]);
      cprintf("%s PROBLEM:", type[op]);
      gotoxy(col, 12);
      cprintf("Type in the %s: ", arg1[op]);
      scanf("%d", &num1);
      do    // Add a loop on num2 to make sure num2 != 0 for Divide
      {
         gotoxy(col, 13);
         cprintf("Type in the %s: ", arg2[op]);
         scanf("%d", &num2);
      }while(op == Divide && num2 == 0);  // Check for divide by 0
      gotoxy(col, 14);
      cprintf("What do you think is the answer %s? ", ask[op]);
      scanf("%d", &guess);
      switch(op)
      {
         case Add:       ans = num1 + num2; break;
         case Subtract:  ans = num1 - num2; break;
         case Multiply:  ans = num1 * num2; break;
         case Divide:    ans = num1 / num2; break;
      }
      gotoxy(col, 15);
      cprintf("The answer is ");
      textcolor(15);
      cprintf("%d", ans);
      textcolor(2);
      gotoxy(col, 16);
      cprintf("You guessed %s", (ans == guess) ? "right!" : "wrong.");
      gotoxy(col, 18);
      cprintf("Would you like to try another (Y/N)? ");
      do
      {
         guess = (0 == (guess = getch())) ? -getch() : guess;
         guess = toupper(guess);
      } while(guess != 'Y' && guess != 'N');
   } while(guess == 'Y');  // If yes, loop through calc() again
   return 0;
}
  
void promptc(int x, int y, int color, const char *p)
{
   gotoxy(x,y);
   textcolor(color);
   cputs(p);
}
Cliff Rhodes
cliff.rhodes@juge.com
crhodes@flash.net
X CMPQwk 1.42 1692 X"When Love is suppressed Hate takes its place." - 
Havelock Ellis
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