What's the difference between "&" in this program

Question

Below is part of a C++ program:

Circle circle1, &circle2 = circle1, *p = &circle2;

I'm wondering what is the difference in between the two &s there? Thanks so much.

Read this : http://stackoverflow.com/questions/57483/what-are-the-differences-between-a-pointer-variable-and-a-reference-variable-in — SolarBear, May 18 '15 at 03:43

score 6 · Accepted Answer · answered May 18 '15 at 03:48

6

The first (use of &) is declaring a Circle reference and the latter is the address-of operator for obtaining the memory address of circle2.

answered May 18 '15 at 03:48

Tas

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score 4 · Answer 2 · answered May 18 '15 at 03:50

4

Circle circle1, &circle2 = circle1, *p = &circle2;

is equivalent to:

Circle circle1;
Circle &circle2 = circle1;  // & is used to declare a reference variable
Circle *p = &circle2;       // & is used to take the address of circle2

answered May 18 '15 at 03:50

R Sahu

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score 1 · Answer 3 · answered May 18 '15 at 05:09

They have two very different meanings. Its easier to see if you split up the terms.

Circle circle1; // A Circle object

Circle& circle2 = circle1; // A Circle reference

Circle* p = &circle2; // A Circle pointer takes the address of a Circle object

In the second line you are declaring a reference to a Circle.

In the third line you are taking the address of a Circle.

So the second line is using & to declare a reference type.

The third line is using & as the address of operator.

What's the difference between "&" in this program

3 Answers3