Passing row of static 2-d array to function in C++
This is a really elementary question. Nonetheless, I haven't found a solution after st开发者_运维技巧udying dozens of semi-relevant examples online.
I have a two-dimensional array of doubles whose size is known at compile time: double demPMFs[ NUM_DEM_PARAMS ][ NUM_AGE_CATEGORIES ]
. Array entries are populated by input files early in the program. I'd like to pass individual rows as one-dimensional arrays to functions later in the program. I'd ideally like to maintain separate names for each row:
#define LSPAN_PMF demPMFs[0][]
#define FLEDGE_PMF demPMFs[1][]
#define PAIR_PMF demPMFs[2][]
#define BIRTH_AGE_PMF demPMFs[3][]
#define SPLIT_AGE_PMF demPMFs[4][]
(Here, NUM_DEM_PARAMS = 5;
). Below is a failed attempt to pass a row to a function:
int calcDeath( double demPMFs[][ NUM_AGE_CATEGORIES ] ) {
int age_death = rmultinom( LSPAN_PMF, NUM_AGE_CATEGORIES );
return age_death;
}
int rmultinom( const double p_trans[], int numTrans )
// ...[code snipped]...
}
I'm getting compiler errors about the prototypes now; I expect to run into problems with the const
declaration too. I can go into the details of the errors if people think they're relevant, but I suspect there's a lot to set straight already.
Instead of using array[index][]
, use array[index]
:
#define LSPAN_PMF demPMFs[0]
// ... etc.
But why obfuscate working with arrays so much? Using named indices would be much clearer:
enum {
IndexLspan,
IndexFledge,
// ...
};
int calcDeath( double demPMFs[][ NUM_AGE_CATEGORIES ] ) {
int age_death = rmultinom( demPMFs[IndexLspan], NUM_AGE_CATEGORIES );
Continuing, why not use the containers from the C++ standard library in the first place?
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