Std::Max - Expected an Identifier

std::max - expected an identifier

Hazarding a guess, since you're using VC++ – put this before any #includes:

#define NOMINMAX

windows.h defines macros named min and max like so:

#define min(a,b)            (((a) < (b)) ? (a) : (b))
#define max(a,b)            (((a) > (b)) ? (a) : (b))

The Windows SDK has contained these macros since before C++ was standardized, but because they obviously play havoc with the C++ standard library, one can define the NOMINMAX macro to prevent them from being defined.

As a rule, if you're using C++ (as opposed to C) and including windows.h, always define NOMINMAX first.

std::cin.ignore(std::numeric_limitsstd::streamsize::max(), '\n') error when using #include Windows.h

The <windows.h> header has had the min() and max() macros since time immemorial, and they frequently cause problems with C++. Fortunately, you can disable them by adding #define NOMINMAX before including <windows.h>.

Problem calling std::max

You are probably including windows.h somewhere, which defines macros named max and min.

You can #define NOMINMAX before including windows.h to prevent it from defining those macros, or you can prevent macro invocation by using an extra set of parentheses:

column = (std::max)(1u, column + count);

Why is std::min failing when windows.h is included?

The windows.h header file (or more correctly, windef.h that it includes in turn) has macros for min and max which are interfering.

You should #define NOMINMAX before including it.

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In fact, you should probably do that even if there were no conflict, since the naive definition of the macro shows why function-like macros are a bad idea:

#define max(a,b) ((a)>(b)?(a):(b))

If you invoke that macro with, for example:

int x = 5, y = 10;
int c = max(x++, y--);

then y will not end up with what you expect. For example, it will expand to:

int c = ((x++)>(y--)?(x++):(y--));

That expression (unless undefined behaviour kicks in which would be even worse) will decrement y twice, not something you're likely to expect.

I basically use macros only for conditional compilation nowadays, the other two major use cases of old (symbolic constants and function-like macros) are better handled with more modern language features (real enumerated types and inline function suggestion).

Syntax error with std::numeric_limits::max

Your problem is caused by the <Windows.h> header file that includes macro definitions named max and min:

#define max(a,b) (((a) > (b)) ? (a) : (b))

Seeing this definition, the preprocessor replaces the max identifier in the expression:

std::numeric_limits<size_t>::max()

by the macro definition, eventually leading to invalid syntax:

std::numeric_limits<size_t>::(((a) > (b)) ? (a) : (b))

reported in the compiler error: '(' : illegal token on right side of '::'.

As a workaround, you can add the NOMINMAX define to compiler flags (or to the translation unit, before including the header):

#define NOMINMAX   

or wrap the call to max with parenthesis, which prevents the macro expansion:

size_t maxValue_ = (std::numeric_limits<size_t>::max)()
//                 ^                                ^

or #undef max before calling numeric_limits<size_t>::max():

#undef max
...
size_t maxValue_ = std::numeric_limits<size_t>::max()

Error: Expected Identifier

You defined Mob to... nothing. That makes your code equivalent to:

class {
private:
    int lvl;
    float hp;
public:
    (int, float); // Expecting an identifier indeed
};

and that holds for the rest of the code where #define Mob is included.

If you're trying to make include guards, you need a unique name and define it conditionaly:

#ifndef UNIQUE_MOB
#define UNIQUE_MOB
// code
#endif

#define NOMINMAX using std::min/max

If you're really desperate, put parentheses around the function names:

(std::min)(x, y);

This syntax won't apply a function-like macro. (Formally, to apply a function-like macro the name of the macro must be followed by optional white space then a '('.)

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