Re: Macro question
Peithon wrote:
I'm initialising unit test structures using a macro as follows:
#define UTMACRO(x) UT##x
typedef struct
{
char * key;
char * arr[5];
}unit_test;
1. 'typedef struct { } name;' is useless in C++. Use 'struct name { };'.
2. Use std::string by default.
3. If you really don't want to, use char const*, the conversion of string
literals to non-const char* is deprecated and error-prone.
4. Use std::map<> for associative containers (I guess that was what you
wanted).
unit_test UT1 = { "three", { "five", "four", "one", "three",
"two" } };
unit_test UT2 = { "two", { "five", "four", "one", "three",
"two" } };
for(i = 0; i < TEST_NUM; i++)
{
unitTest[i] = UTMACRO(i + 1);
}
[...]
but the compiler is resolving UTMACRO(i + 1) as UT rather than UT1 and
then UT2.
You are misunderstanding the way that macros work. They are commonly called
part of the preprocessing stage. In that stage, the sourcecode is mostly
treated as text, so no interpretation of the variable 'i' is done!
Therefore, it simply replaces that macro invocation with 'UT##i + 1'.
However, it seems you are treating UT1 and UT2 as an array, so why not make
them an array? In fact you did so, but not with the initial values. Try
this:
size_t const size = 2;
unit_test UT[size] = {....};
for( size_t i=0; i!=size; ++i)
UT[i] = ...
Why? Can this be fixed or does anyone have a better way of performing
this task.
I'm not even exactly sure what the task is, btw.
Uli
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