Initializing struct, using an array

Question

I have a couple of array's:

const string a_strs[] = {"cr=1", "ag=2", "gnd=U", "prl=12", "av=123", "sz=345", "rc=6", "pc=12345"};
const string b_strs[] = {"cr=2", "sz=345", "ag=10", "gnd=M", "prl=11", "rc=6", "cp=34", "cv=54", "av=654", "ct=77", "pc=12345"};

which i then need to parse out for '=' and then put the values in the struct. (the rc key maps to the fc key in the struct), which is in the form of:

struct predict_cache_key {
    pck() :
        av_id(0),
        sz_id(0),
        cr_id(0),
        cp_id(0),
        cv_id(0),
        ct_id(0),
        fc(0),
        gnd(0),
        ag(0),
        pc(0),
        prl_id(0)
    { }

    int av_id;
    int sz_id;
    int cr_id;
    int cp_id; 
    int cv_id;
    int ct_id;
    int fc;
    char gnd;
    int ag;
    int pc;
    long prl_id;
};

The problem I am encountering is that the array's are not in sequence or in the same sequence as the struct fields. So, I need to check each and then come up with a scheme to put the same into the struct.

Any help in using C or C++ to solve the above?

Answer 1

Probably I didn't get it correctly, but obvious solutions is to split each array element into key and value and then write lo-o-ong if-else-if-else ... sequence like

if (!strcmp(key, "cr"))
   my_struct.cr = value;
else if (!strcmp(key, "ag"))
   my_struct.ag = value;
...

You can automate the creation of such sequence with the help of C preprocessor, e.g.

#define PROC_KEY_VALUE_PAIR(A) else if (!strcmp(key,#A)) my_struct.##A = value

Because of leading else you write the code this way:

if (0);
PROC_KEY_VALUE_PAIR(cr);
PROC_KEY_VALUE_PAIR(ag);
...

The only problem that some of you struct fields have _id sufffix - for them you'd need to create a bit different macro that will paste _id suffix