#include <iostream>
using namespace std;

void EnterOperator(char &opchar)
{
cout << "Enter an operation to perform { + - / * } ";
cin >> opchar;
}

void ReadFraction(int &Num, int &Denom, int &Num2, int &Denom2)
/* This function will allow the user to enter two fraction. */
{
cout << "Enter the numerator and denominator for the first fraction; include a space: ";
cin >> Num >> Denom;
cout << endl;
cout << "Enter the numerator and denominator for the second fraction; include a space: ";
cin >> Num2 >> Denom2;
cout << endl;

}

//-------------------------------------------------------------------



void AddFraction(int &Num, int &Denom, int &Num2, int &Denom2)
/* This function is called after Reduce. This function adds the two
fractions Reduce() reduced
Pre: Two Fractions
Post: One reduced fraction */
{
if (Denom != Denom2)
{


Num = Num * Denom2;
Num2 = Num2 * Denom;
Denom = Denom * Denom2;
Denom2 = Denom2 * Denom;
Num = Num + Num2;
}
else
{
Num = Num + Num2;
}


}

void SubFraction(int &Num, int &Denom, int &Num2, int &Denom2)
/* This function is called after Reduce. This function adds the two
fractions Reduce() reduced
Pre: Two Fractions
Post: One reduced fraction */
{
if (Denom != Denom2)
{


Num = Num * Denom2;
Num2 = Num2 * Denom;
Denom = Denom * Denom2;
Denom2 = Denom2 * Denom;
Num = Num - Num2;
}
else
{
Num = Num - Num2;
}

}


void DisplayFraction(int &Num, int &Denom)
/* This function displays the reduced and added fraction. This
function is called after AddFraction()
Post: Prints fraction */
{
cout << "The fraction value is: " << Num << "/" << Denom << endl;
}


int main()
{
char an;
int op;


do
{
int Num, Denom, Num2, Denom2 = 0;
char opchar;
EnterOperator(opchar);
ReadFraction(Num, Denom,Num2,Denom2);
AddFraction(Num, Denom, Num2, Denom2);
SubFraction(Num, Denom, Num2, Denom2);
DisplayFraction(Num, Denom);
cout << endl;

switch (opchar) {
case '+':
op = ;
break;
case '-':
op = ;
break;

default: // If operator is illegal shut program down
cout << "Invalid operator." << endl;

int gcd(int Num, int Denom ) {
assert(Denom != 0);
int rem = Num % Denom;

while(rem !=0 ){
Num = Denom;
Denom = rem;

rem = Num % Denom;

}

return Denom;

}
}

cout <<"Would you like to do another fraction? ";
cin >> an;
cout << endl;
} while ((an == 'y') || (an == 'Y'));


return(0);
}

switch (opchar) {
  case '+':
    op = ;  //Call function
    break;
  case '-':
    op = ;  //Call function
    break;
  case '*':
    op = ; //Call Function.
    break;
  case '/':
    op =  //Call function.
    break;

  default: // If operator is illegal shut program down
    cout << "Invalid operator." << endl;

{
    int aVal, bVal;

...

    value = AddNumbers(aVal, bVal);    // add a + b
...
}

// The value aVal above will enter the function as val1, bVal as val2
int  AddNumber(int val1, val2)    // receives two ints, returns an int
{
    int rtnvalue;    // the answer...

    rtnvalue = val1 + val2;    // calculate the sum
    return  rtnvalue;            // return the sum
}