#include <iostream>
#include <cstdlib>
using namespace std;
 
int main()
{
  int num, numer, denom;  // number of fractions, numerator, denominator
  char slash;  // storage for '/' symbol.
 
  cin >> num;
  cout << "num= " << num << endl;
 
  for (int i=0; i<num; i++)
    {
      cin >> numer;
      cin >> slash;
      cin >> denom;
      cout << "numer= " << numer << endl;
      cout << "slash= " << slash << endl;
      cout << "denom= " << denom << endl;
 
////////////////////////////////////
// ERROR HAPPENS AFTER THIS POINT //
////////////////////////////////////
 
      cout << numer;
      cout << slash;
      cout << denom;
 
      if (denom = 0)
        cout << " ==> is invalid because denominator is zero";
      if (denom < 0)
        {
          numer = numer * -1;
          denom = abs(denom);
        }
 
      if (denom > 0)
        cout << " ==> " << numer << "/" << denom;
 
      if (numer/denom > 0)
        cout << " ==> " << numer/denom << " " << abs(numer%denom) << "/"<< denom;
 
      cout << endl;
 
      cin >> numer >> slash >> denom;
    }
  return 0;
}

if(denom==0)

char slash = '/';