I'm trying to write code for a very basic version of the game 24. This code will receive either two, three, or four integers and determine if there is any way that these numbers can add, subtract, multiply or divide to the number 24. Locations of parenthesis can change as well. I handled the two integer case easily, and now am working on the three integer case and so far have the following function.

The above compiles correctly, but when it is run I get "floating point exception." I've read through some posts on the forum and this error is typically the result of a divide by zero or invalid array address. I am thinking that my problem is of the latter, because I have just started using arrays and am not too sure how to use them properly.

Any suggestions to improve this algorithm are welcome as well, Thanks!

EDIT: Sorry for posting the snippet, I realized after that thats not the right way to post.

bool makeSumQ(int num1, int num2, int num3)
{
  
  bool ans;
  
  int a[6], b[6], c[6], d[36], e[36], f[36];
  
  alg(num1, num2, a, 0);
  alg(num1, num3, b, 0);
  alg(num2, num3, c, 0);

  for (int i = 0; i < 6; i++)
    { 
      alg(num3, a[i], d, i);
      alg(num2, b[i], e, i);
      alg(num1, c[i], f, i);
    }

   
  for (int i = 0; i < 36; i++){
    if ((d[i] == 24) ||  (f[i] == 24) ||  (c[i] == 24))
      {
	ans = true;
	break;
      }
    else
      {
	ans = false;
      }
  }



  return ans;
}
    
    


//Function finds all six poss combinations of the variable

void  alg(int num1, int num2, int poss[], int iteration){
  
  int address = iteration * 6;
  
  
  poss[0 + address] = num1 + num2;
  poss[1 + address] = num1 - num2;
  poss[2 + address] = num2 - num1;
  poss[3 + address] = num1 * num2;
  poss[4 + address] = num1 / num2;
  poss[5 + address] = num2 / num1;
  
}
bool makeSumQ(int num1, int num2, int num3)
{
  
  bool ans;
//Define the arrays to store the results of the operations
  
  int a[6], b[6], c[6], d[36], e[36], f[36];

//Calculate every possible outcome for two of the three numbers
  alg(num1, num2, a, 0);
  alg(num1, num3, b, 0);
  alg(num2, num3, c, 0);

//Plug each of the results from the previous operation back into the alg function to find all possible
//totals for three numbers

  for (int i = 0; i < 6; i++)
    { 
      alg(num3, a[i], d, i);
      alg(num2, b[i], e, i);
      alg(num1, c[i], f, i);
    }

 //Test to see if 24 is in any of the possible solutions
  for (int i = 0; i < 36; i++){
    if ((d[i] == 24) ||  (f[i] == 24) ||  (c[i] == 24))
      {
	ans = true;
	break;
      }
    else
      {
	ans = false;
      }
  }



  return ans;
}

void  alg(int num1, int num
  return ans;2, int poss[], int iteration){
  
  int address = iteration * 6;
  
  
  poss[0 + address] = num1 + num2;
  poss[1 + address] = num1 - num2;
  poss[2 + address] = num2 - num1;
  poss[3 + address] = num1 * num2;
  poss[4 + address] = num1 / num2;
  poss[5 + address] = num2 / num1;
  
}

Edited 6 Years Ago by wdow: n/a

You are dividing by 0 on line 52 whenever num2 = 0 and similarly for num1 on line 53. Also, unless I'm overlooking something, you have not initialized the values in the a, b and c arrays, so when you send elements of those arrays as the 2nd parameter in alg() you are sending undefined garbage.

That is true for the divide by zero, I forgot to take into account that if num1 - num2 = 0 then when you try and divide num3 by that combination it is a divide by zero error.

I understand that a, b, and c are not initialized as well, but how can I get the first function to output an array of the 6 possible results for the two numbers? I tried to apply an example from my text book but I guess I was unsuccessful.

Thanks for such a fast response!

Well now the program runs with conditionals added, but unfortunately my algorithm is incorrect. But at least there is progress.

EDIT: Figured out why it wasn't working, stupid typo...

Edited 6 Years Ago by wdow: n/a

Frankly, I don't see what the a b and c arrays are supposed to represent, and I don't know what

how can I get the first function to output an array of the 6 possible results for the two numbers?

means. Which two numbers?

The a, b, and c arrays represent all the possible ways that one could perform an algebraic operation on two numbers. Each one (a, b, and c) stores the 6 results from the algebraic operations on the three possible number pairs. Your solution earlier fixed the problem, and the program now works just fine, thanks again!

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