What is the difference between * and & in function parameters?

Question

I have seen something in this form:

void function( A_struct &var ) {
   var.field0 = 0;
   // ...
}

Since there is & before var, I thought that var is a pointer. But in the body, instead of writing var->field0, var.field0 is written. So, my questions are:

Isn't var a pointer?
What is the difference between writing A_struct &var and A_struct *var in function parameter?

This is illegal in C. You must be looking at C++ code and not realize it. — M.M, May 27 '15 at 13:02
You can think of a reference as `an automatically dereferenced constant pointer`, so it almost looks like the copy of variable itself. You can read more about reference in any basic C++ book. — Mohit Jain, May 27 '15 at 13:05

score 4 · Answer 1 · edited May 23 '17 at 12:14

4

A syntax like A_struct &var is not valid in context of C.

It is used in case of C++ to denote pass-by-reference.

Related: See this question and related answers for more details.

edited May 23 '17 at 12:14

Community

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answered May 27 '15 at 13:01

Sourav Ghosh

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score 1 · Accepted Answer · answered May 27 '15 at 13:12

Your question is actually related to C++

void function(A_struct &var) is not valid for C because in C it is used to get an address of a variable. In C++ it is a type of variable which is known as reference. You can see an example of it in here

void function(A_struct *var) is allowed in C and C++, because is a pointer which holds the address of A_struct type variable's address.

What is the difference between * and & in function parameters?

2 Answers2