static conversion of integer constant to const char*

Question

I have an integer constant known at compile time (but not at code-writing time) and I would like to generate, also at compile time, a const char* holding them as ASCII. For example

const int  C         = IntegerConst;
const char*C_as_text = StaticConvert(A);

such that if IntegerConst is given in some #included header file, say IntegerConst=42, than C_as_text="42".

Any idea how to get such a StaticConvert() functionality? In principle this must be possible, as the compiler and preprocessor have all the necessary information at hand.

See here http://stackoverflow.com/questions/6713420/c-convert-integer-to-string-at-compile-time. — Dabbler, Nov 01 '11 at 11:52
If the number is itself a constant expression that's the result of some computation (maybe `sizeof(MyType)`?), we could discuss a template solution... — Kerrek SB, Nov 01 '11 at 12:22

score 3 · Answer 1 · answered Nov 01 '11 at 11:57

3

You can use preprocessor directive:

#define StaticConvert(N) #N

Here the condition is that you need to provide the number itself as N. e.g.

const int C = 42;
const char *C_as_test = StaticConvert(42);

answered Nov 01 '11 at 11:57

iammilind

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well, this will not do in my case, since C is not a literal. – Walter Nov 01 '11 at 20:21

score 2 · Answer 2 · answered Nov 01 '11 at 11:58

2

The 'stringize' preprocessor operator:

#define StaticConverter(V) #V

const char *x = StaticConverter(56);
assert(x[0] == '5' && x[1] == '6' && x[2] == 0);

answered Nov 01 '11 at 11:58

CapelliC

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score 0 · Answer 3 · answered Nov 01 '11 at 11:56

0

Use the preprocessor's stringizing operator.

answered Nov 01 '11 at 11:56

Skizz

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static conversion of integer constant to const char*

3 Answers3