alias/reference variable in C

[dansmahajan]

It may be a stupid question but I'm not able to find the answer- why there is no reference variable in C like C++??

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Like in C++:
int a;
int& b = a;

I think answer might be some approved C standard but i'm not sure, so what do you think ??

[Icee]

Because references are basically pointer sugar, and C was specifically designed to have explicit pointer operations and as little sugar as possible.

[dansmahajan]

@Icee: Thank you very much.

[Wajideu]

You could probably get away with this though

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int *a = ({ static int _a = 0; &_a }); 

It's part of a gcc function expression extension, so it definitely won't work in most compilers (if at all)

[dansmahajan]

@DaemonR: Thank you.
But this will again involve pointers(which are apparent to programmers) and will have their own memory address whereas in C++ reference variables variable and its alias share the same memory address(Correct me if I'm wrong).

[Wajideu]

@DaemonR: Thank you.
But this will again involve pointers(which are apparent to programmers) and will have their own memory address whereas in C++ reference variables variable and its alias share the same memory address(Correct me if I'm wrong).

This in C++

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int &a;
a += 1;

Is roughly the same as this in C:

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int _a, *a = &_a;
*a += 1;

It's just syntactical sugar.

[Brendan]

Hi,

This in C++

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int &a;
a += 1;

Is roughly the same as this in C:

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int _a, *a = &_a;
*a += 1;

It's just syntactical sugar.

Yes; and this in C++:

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void foo(int &var) {
    var++;
}

Is roughly the same as this in C:

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void foo(int *var) {
    (*var)++;
}

Except for the fact that in C the caller would do "foo(&bar);" (which makes it obvious that bar may be modified), and in C++ the caller does "foo(bar);" where it looks like the variable is passed by value and safe from modification when it's not.

This is what makes it "syntactical sugar poured into your gas tank".


Cheers,

Brendan

[bluemoon]

Except for the fact that in C the caller would do "foo(&bar);" (which makes it obvious that bar may be modified), and in C++ the caller does "foo(bar);" where it looks like the variable is passed by value and safe from modification when it's not.

Agree, therefore I still pass by pointer when the value would be modified, although this means adding an extra a null check.

Pass by reference is still useful when it's const:

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int foo(const MyClass& c) {
    return c.get_foo();
}