Go4Expert - declaring function that returns a structure

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declaring function that returns a structure

Hi, anyone knows why the highlighted words cause syntax errors?
Please advise.

Code:

#include <stdio.h>

#include <ctype.h>

#include <string.h>

//declare structure

struct result

{

        int num_a=0, num_b=0;

};

//declare function prototype 

struct result count( char str[], int idx );



int main()

{

        char str[] = "acdefAbbA";

        struct result res = count( str, 0 );

        /*char *pa=res.num_a, *pb=res.num_b;*/

        

        printf( "num a = %d and num b = %d\n", res.num_a, res.num_b );

        // should output : "num_a = 1 and num_b = 2"

        

        

        return 0;

}



struct result count( char str[], int idx )

{

        switch( str[idx] )

        {

                struct result res;

                case 'a':

                                (res.num_a)++;

                                idx++;

                                return count( str[idx], idx);

                case 'b':

                                (res.num_b)++;

                                idx++;

                                return count( str[idx], idx);

                case '\0':

                                return res;

        }

}

Re: declaring function that returns a structure

(1) int num_a=0, num_b=0;

This one causes error because C (or C++) does not allow in-struct (or in-class) initialization of non-const static member variables.
You should define the struct without initializations and then initialize num_a and num_b to 0 whenever you declare a new variable of that struct type.

(2) return count( str[idx], idx);

The count function you have defined :

Code: CPP

struct result count( char str[], int idx )

accepts a character array and an integer.
But you are passing a character ... str[idx].

Re: declaring function that returns a structure