C++ object creating

[madhukarti]

In one of my project I am going through some code. I need some help on this.

Code Snipnet:

class B{};
class A{
public:
void method1(B* b){
b = new B();
}
void method2(B*& b) {
b = new B();
}
};
int main(void){
A a;
B* b = new B;
a.method1(b);
a.method2(b);
}

What is the difference between method1 and method2

Thanks in advance
Madhu

[Cabhan]

This sounds a bit like a homework problem, which are not allowed on these forums.

However, I'll give you a bit of advice (and if it's not a homework problem, please let us know).

The difference lies in the '&' in the parameter list. For simplicity's sake, assume that the parameters are not pointers; assume, for instance, that the actual code is:

void method1(string s){
    s = "foo";
}
void method2(string &s) {
    s = "foo";
}

This is a technique called pass-by-reference, where modifying a parameter modifies the parameter that was used to call the function.

There are a number of resources online that explain this well.