Returning Array from Function

can any one please explain me this code :-

Code:

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#include<stdio.h>
#include<conio.h>

#define ROW 3
#define COL 4

int main()

{
        int i,j;
        int(*c)[ROW][COL];
        int (*fun3())[ROW][COL];
       

        c=fun3();
        printf("Array c[][] in main():\n");
        for(i=0;i<ROW;i++)
        {
        for(j=0;j<COL;j++)
                printf("%d\n",(*c)[i][j]);
        printf("\n");
        }
        _getch();
        return 0;
}

int (*fun3())[ROW][COL]
{
        static int c[ROW][COL]={
                                                                6,3,9,1,
                                                                2,1,5,7,
                                                                4,1,1,6

                                                        };

int i,j;
printf("Aray c[][] in fun3():\n");
for(i=0;i<ROW;i++)
{
        for(j=0;j<COL;j++)
        {
                printf("%d",c[i][j]);
        printf("\n");
        }
}
return (int(*)[ROW][COL])c;
}

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i am not getting
1.

Code:

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int (*fun3())[ROW][COL];

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2. working of this :-

Code:

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for(i=0;i<ROW;i++)
        {
        for(j=0;j<COL;j++)
                printf("%d\n",(*c)[i][j]);

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3.

Code:

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return (int(*)[ROW][COL])c;

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please explain and suggest some site/blog/book where i can read on this

You're probably mixing up types, although I haven't looked closely. A typedef is usually a handy helper to avoid confusion, particularly if you are playing with functions returning pointers to non-trivial things.

Code:

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#include <stdio.h>

#define ROW 3
#define COL 4


typedef int YourArray[ROW][COL];

int main()
{
    YourArray *fun3();
    YourArray *c = fun3();
    /* print out array as in your code */
    return 0;
   
}

YourArray *fun3()
{
        static int c[ROW][COL]={
                                                                6,3,9,1,
                                                                2,1,5,7,
                                                                4,1,1,6

                                                        };
        return &c;
}

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First C cannot return an array from a function... it doesn't know how. The best you can get is a pointer which may or may not be valid after the function returns... Here's a little test program you can run to see why you should not do this...

Code:

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#include <stdio.h>

int* MyFunction(int a, int b, int c)
  {  static int array[3];
    array[0] = a;
    array[1] = b;
    array[2] = c;
    return array;  } // return a pointer.


int main (void)
  { int *a1, *a2;  // int pointers

    printf("calling a1 = MyFunction(10,20,30);\t");
    a1 = MyFunction(10,20,30);
    printf("a1 has %d %d %d\n",a1[0],a1[1],a1[2]);

    printf("calling a2 = MyFunction(100,200,300);\t");
    a2 = MyFunction(100,200,300);
    printf("a2 has %d %d %d\n",a2[0],a2[1],a2[2]);

    printf("\nLooks good, except...\t");
    printf("a1 now has %d %d %d\n",a1[0],a1[1],a1[2]);

    getchar();
    return 0; }

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Quote:

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Originally Posted by tarunjain07

can any one please explain me this code :-

Code:

---

#include<stdio.h>
#include<conio.h>

#define ROW 3
#define COL 4

int main()

{
        int i,j;
        int(*c)[ROW][COL];
        int (*fun3())[ROW][COL];
       

        c=fun3();
        printf("Array c[][] in main():\n");
        for(i=0;i<ROW;i++)
        {
        for(j=0;j<COL;j++)
                printf("%d\n",(*c)[i][j]);
        printf("\n");
        }
        _getch();
        return 0;
}

int (*fun3())[ROW][COL]
{
        static int c[ROW][COL]={
                                                                6,3,9,1,
                                                                2,1,5,7,
                                                                4,1,1,6

                                                        };

int i,j;
printf("Aray c[][] in fun3():\n");
for(i=0;i<ROW;i++)
{
        for(j=0;j<COL;j++)
        {
                printf("%d",c[i][j]);
        printf("\n");
        }
}
return (int(*)[ROW][COL])c;
}

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Quote:

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i am not getting
1.

Code:

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int (*fun3())[ROW][COL];

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Hi this is function declaration. This meaning function(fun3) returning an pointer to an two dimentional array of width(row) and height(col)

Quote:

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2. working of this :-

Code:

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for(i=0;i<ROW;i++)
        {
        for(j=0;j<COL;j++)
                printf("%d\n",(*c)[i][j]);

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here you are going to print the values in two dimensional array. Actually c is pointer to two dimensional array. so you can get those values by (*c)[i][j].

Quote:

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3.

Code:

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return (int(*)[ROW][COL])c;

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Here the function returning the pointer(c) to an two dimensional array. Because we already declared this function prototype in main fucntion.

Quote:

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please explain and suggest some site/blog/book where i can read on this

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Quote:

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Originally Posted by tarunjain07

i am not getting
...

Code:

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return (int(*)[ROW][COL])c;

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That cryptic cast is pointless, when just returning a pointer to "c" is enough:

Code:

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return &c;

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