i have a code for complex number but when i key in 7+i3 and 5+i2 into the operator+ it should return me the result of 12,5 but i receive 430. What is the problem wif my code?

```
class Complex
{
friend istream& operator>>(istream&, Complex&);
friend ostream& operator<<(ostream&, const Complex&);
public:
Complex(int, int); // constructors
Complex operator +(Complex);
private:
int a, b;
};
Complex::Complex( int _a=0, int _b=0 )
{
a = _a;
b = _b;
}
istream& operator>>(istream &in, Complex &num)
{
string line="";
in>>line;
for(int i=0; i<line.length(); i++)
{
if(i==1)
{
num.a = line[i];
}
else if(i==4)
{
num.b = line[i];
}
}
return in;
}
ostream& operator<<(ostream &out, const Complex &num)
{
out<<num.a;
out<<num.b;
return out;
}
Complex Complex::operator +(Complex t)
{
Complex temp;
temp.a = a + t.b;
return temp;
}
int main()
{
Complex A, B, C;
cout << "Enter first complex number, format (a+ib): ";
cin >> A;
cout << "Enter second complex number, format (a+ib): ";
cin >> B;
C = A + B;
cout << "Addition A + B = " << C << endl;
system("pause");
return 0;
}
```