Functions that return structures

I've been trying to create a code that includes structures produced at various event times by a function. Since it was clear that my structure-producing function was not working, I decided to try building a very simple code that just produces a structure from a function.

Not surprisingly, it doesn't work either. It returns an error saying "funs returning structs/unions illegal '=makepoint(1,1)' ".

Code:

---

#include <stdio.h>
 #include <stdlib.h>
 #include <time.h>       
 #include <math.h>

struct point {
        int x;
        int y;
};
struct point makepoint(int a, int b);       

int main() {
        struct point point1;
       
        point1=makepoint(1,1);
       
        printf( "done" );

        getchar();
        return 0;

}

struct point makepoint(int a, int b) {
        struct point new;
       
        new.x=a;
        new.y=b;
       
        return new;
}

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I presume I'm making a really elementary coding error. :confused:

new is a local instance of point that'll be destroyed once the function returns. generally passing around and returning full structs creates alot of unnecessary overhead. instead, try passing a pointer to the struct.

Code:

---

#include <stdio.h>
 #include <stdlib.h>
 #include <time.h>       
 #include <math.h>

struct point {
        int x;
        int y;
};
void makepoint(int a, int b, struct point *ppt);       

int main() {
        struct point point1;
       
        makepoint(1,1,&point1);
       
        printf( "done" );

        getchar();
        return 0;

}

void makepoint(int a, int b, struct point *ppt) {
        ppt->x=a;
        ppt->y=b;
}

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This is how to do it with dynamic memory.

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <time.h>       
#include <math.h>

struct point {
        int x;
        int y;
};

struct point * makepoint(int a, int b);       

int main() {
        struct point * point1;  // declare a pointer
       
        point1=makepoint( 1, 1 );  // a pointer to the struct is returned
       
        printf( "done. x=&#37;d, y=%d\n", point1->x, point1->y  );

        free(point1) ;  // release the struct's memory
       
        getchar();
        return 0;

}

struct point * makepoint(int a, int b) {
        struct point * mypoint;  // Declare a pointer to a point struct
        mypoint = malloc(sizeof(struct point) ) ;  // Obtain dynamic memory 
       
        mypoint->x=a;  // assign values
        mypoint->y=b;
       
        return mypoint ;  // return the pointer to the struct
}

---

Quote:

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Originally Posted by Burra

It returns an error saying "funs returning structs/unions illegal '=makepoint(1,1)' ".

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What compiler are you using?

Quote:

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Originally Posted by Dave_Sinkula

What compiler are you using?

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Good question. As it happens, I was using Miracle C, and when I switched to CodeBlocks, it worked (after I renamed "new").

Thanks, Bleech and Todd.