Array of structs - deleting/adding elements and printing

[hitholdir]

Hi,

For the below code

struct orderSlip
{
	char source[64];
	char destination[64];
	char item[64];	
	int position;
};
//global
struct orderSlip data[100];

Is there another way of printing out the data for each element other than doing this:

		printf("%s\n",data[0].source);
		printf("%s\n",data[0].destination);
		printf("%s\n",data[0].item);
		printf("%i\n\n", data[0].position);
		
		printf("%s\n",data[1].source);
		printf("%s\n",data[1].destination);
		printf("%s\n",data[1].item);
		printf("%i\n", data[1].position);
etc

or using a for loop like this?

	for(int n = 0; n< 3; n++)
	{
		printf("%s\n",data[n].source);
		printf("%s\n",data[n].destination);
		printf("%s\n",data[n].item);
		printf("%i\n\n", data[n].position);
	}

For deleting and adding, do I have to make a dynmaic array of structs? If so, what would be the simplest syntax to do that?

int * bobby;
bobby = new int [5];
delete bobby[5];

but in C? I'm guessing its malloc and free

[Volatile Pulse]

While using C, I don't know of a way to "overload" the printf function to display your struct. I can't remember if structs allow for functions (I don't believe they do), but in C++ classes/structs, you have the option of creating a Display() method that can print your each of your structures.

As for deleting/creating objects, I'm not very familiar with C in that sense either, but I do believe your only option is malloc/free.

[ToniAz]

What I would do is start off with an array with "this number of elements" and for each cell I would add a flag to indicate whether the entry is valid or not. Say you want to store 2 elements, and maybe more later.

This comes is practical in a sense that you don't have to allocate new space, copy data, free old space every single time you want to add an element. This is what sophisticated containers do actually.

[vlad from moscow]

You can either specify a suitable maximum value for the size of the array or dynamically allocate a memory by using malloc, realloc, and free. realloc copies elemebts of the source memory to the destination memory.
To print elements of the array you should of course use a loop. To delete an element you should reorder your array such a way that the deleted element would be the last in the array and then use realloc function.

[AkramIzzeldin]

you can use a function that take orderslip argument and print it.

void printBook( struct Books book )
{
   printf( "Book title : %s\n", book.title);
   printf( "Book author : %s\n", book.author);
   printf( "Book subject : %s\n", book.subject);
   printf( "Book book_id : %d\n", book.book_id);
}

and for your second problem you should use malloc and free
and here is a simple tut about them
http://www.tutorialspoint.com/cprogramming/c_memory_management.htm

i hope that my replay was helpful for u

[Lowest0ne]

As for deleting/creating objects, I'm not very familiar with C in that sense either, but I do believe your only option is malloc/free.

Malloc isn't so bad. Three things to know, 1) It returns a void pointer (so needs casting), 2) it needs an actual Byte amount, 3) The value of the pointer is NULL if not allocated:

int *i = NULL;
int howMany = 5;
i = (int*) malloc (howMany * sizeof(int));
if (i == NULL) printf("couldn't do it\n");

Free is easier than delete, you never use []

free (i);
i = NULL