12. Create a four-function calculator for fractions. The user should type the first fraction, an operator, and a second fraction. The program should then display the result and ask whether the user wants to continue.

Chapter 3: 

Loops and Decisions

Programming Exercise

Problem # 12:

Create a four-function calculator for fractions. (See Exercise 9 in Chapter 2, and
Exercise 4 in this chapter.) Here are the formulas for the four arithmetic operations applied to fractions:
Addition: a/b + c/d = (a*d + b*c) / (b*d)
Subtraction: a/b - c/d = (a*d - b*c) / (b*d)
Multiplication: a/b * c/d = (a*c) / (b*d)
Division: a/b / c/d = (a*d) / (b*c)
The user should type the first fraction, an operator, and a second fraction. The program should then display the result and ask whether the user wants to continue.

Solution:

#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
    int a,b,c,d,resN,resD;
    char dummyChar, ch, choice;
  
    do
    {
        cout<<"Enter operator: ";
        cin>>ch;
        cout<<"Enter first fraction in the form of a/b:";
        cin>>a>>dummyChar>>b;
        cout<<"Enter second fraction in the form of c/d:";
        cin>>c>>dummyChar>>d;
      
        switch(ch)
        {
            case '+':          
                resN=(a*d)+(b*c);
                resD=b*d;
                break;
            case '-':          
                resN=(a*d)-(b*c);
                resD=b*d;
                break;
            case '*':          
                resN=(a*c);
                resD=b*d;
                break;
            case '/':          
                resN=a*d;
                resD=b*c;
                break;
        }
      
        cout<<a<<"/"<<b<<ch<<c<<"/"<<d<<" = "<<resN<<"/"<<resD<<endl;
        cout<<"Do you wish to continue (y/n)?"<<endl;
        choice=getche();
        cout<<endl;
    }while(choice=='y');
  
    return 0;
}

Let me know in the comment section if you have any question.

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