Conversion error

Code:

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int& test(const int& i) {return i;}

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In VC++ I get a compiler error "error C2440: 'return' : cannot convert from 'const int' to 'int &'". I don't know why this is an error, it's just a function taking a const int reference and then returning it. i is not being changed.

You are not allowed to remove const-ness. You could return a const int &, or do a const_cast if you actually know that it's the right thing to do.

This function in itself is pointless, but here are some of your options:

Code:

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const int& test(const int& i) {return i;}
int& test(int& i) {return i;}
int test(const int& i) {return i;}

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You could also use const_cast as tabstop suggested, but for this type of function I think that would be purely evil and dangerous because you can't control how that int& is used once it leaves your function.

Quote:

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Originally Posted by jw232

Code:

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int& test(const int& i) {return i;}

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In VC++ I get a compiler error "error C2440: 'return' : cannot convert from 'const int' to 'int &'". I don't know why this is an error, it's just a function taking a const int reference and then returning it. i is not being changed.

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The compiler is complaining that i is const, and you are returning a non-const reference to it, which means that someone else can access the variable freely - so you are "loosing" the const.

You probably don't actually want to do that, and the suggestions from cpjust shows you some valid alternatives that will all work.

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