C++ program to subtract two fractions

Here are C++ programs to subtract two fractions. First program subtract two fractions using for-loops, and second program uses operator overloading. 

C++ program subtract two fractions using for-loops

#include<iostream>
using namespace std;
int main()
{
    int a1,a2,b1,b2,c1,c2,lcm=1,grtr,d2,e2;
    cout<<"Enter the first fraction number ";
    cin>>a1>>a2;
    cout<<"Enter the second fraction number ";
    cin>>b1>>b2;
    d2=a2,e2=b2;
    if(a2>b2)
        grtr=a2;
    else
        grtr=b2;
    for(int i=2;i<=grtr;i++)
    {
        while(a2%i==0||b2%i==0)
        {
            if(a2%i==0)
                a2=a2/i;
            if(b2%i==0)
                b2=b2/i;
            lcm*=i;
        }
    }
    c1=(a1*(lcm/d2))-(b1*(lcm/e2));
    c2=lcm;
    cout<<"subtraction of two fraction ="<<c1<<"/"<<c2;
    return 0;
}

C++ program subtract two fractions using operator overloading

#include<iostream>
using namespace std;
struct frac{
   int a1,a2;
};
frac operator -(frac a,frac b)
{
    frac c;
    int d2=a.a2,e2=b.a2,grtr,lcm=1;
    if(a.a2>b.a2)
        grtr=a.a2;
    else
        grtr=b.a2;
    for(int i=2;i<=grtr;i++)
    {
        while(a.a2%i==0||b.a2%i==0)
        {
            if(a.a2%i==0)
                a.a2=a.a2/i;
            if(b.a2%i==0)
                b.a2=b.a2/i;
            lcm*=i;
        }
    }
    c.a1=(a.a1*(lcm/d2))-(b.a1*(lcm/e2));
    c.a2=lcm;
    return c;
}
int main()
{
    frac a,b,c;
    cout<<"Enter the first fraction number ";
    cin>>a.a1>>a.a2;
    cout<<"Enter the second fraction number ";
    cin>>b.a1>>b.a2;
    c=a-b;
    cout<<"subtraction of two fraction ="<<c.a1<<"/"<<c.a2;
    return 0;
}