Arrays in Function Arguments

Hello,

I'm wondering if I can list contents in an array within a function argument?

For instance:

Code:

RetreiveArrayInput({2, 1, 3, 0xFF});

I have devised the following code to experiment with, but unfortunately I don't exactly know what I'm doing.

Code:

#include <stdio.h>

//** Defines ************************************************************
#define		TERMINATOR		0xFF

//** Globals ************************************************************
unsigned int ArrayOfMyLife[] = {0x01, 0x02, 0x04, 0x08};

void RetreiveArrayInput(unsigned int *OrderOfValues)
{
     unsigned int i;
     unsigned int index;
     
     while((index = *OrderOfValues++) != TERMINATOR)
     {
			for(i = ArrayOfMyLife[index]; i > 0; i--)
			{
				printf("Selection: %s\n", i);
			}
      }
}

int main()
{
	unsigned int someArray[5];
	RetreiveArrayInput({2, 1, 3, 0xFF});
	
	system("PAUSE");
}

Just in case, I'm using Dev-C++.

Thanks!

Compound Literal
In C99, you can use compound literal.

Code:

RetreiveArrayInput(( unsigned int[]) { 2,1,3, TERMINATOR } ) ;

Which is the same as in C89

Code:

unsigned int __some_anonymous_array[] = { 2,1,3,TERMINATOR };
RetreiveArrayInput( __some_anonymous_array );

Ok, that makes sense. I have another question as well. If I have the following code:

Code:

char a[] = {“Hello”};
char *p;

p = a;		// Does p = “Hello” also?

In other words, it points to the entire quantity of the array? Can I do this?

Code:

printf("%s", p[0]);      // Should this equal 'H' ?

Easy way to find out....

Code:

char a[] = {“Hello”};   // These need to be char not int.
char *p;

p = a;		// Does p = “Hello” also?

puts(p);           // well, lets have a look...

Aha, it does. But doing a p[0] didn't work. I expect I would have to do this:

Code:

p = &a[0];     // This is 'H'

Code:

printf("%s", p[0]);      // Should this equal 'H' ?

You want %c for an individual character. At this point, p points the the start of a, and refers to "Hello". You can index a pointer just like an array, so p[0] == a[0] == 'H', an individual character.

Code:

p = &a[0]

This is the same as p = a, since the name of an array serves as a pointer to it's first element.

Originally Posted by ElectroNerd

Aha, it does. But doing a p[0] didn't work. I expect I would have to do this:

Code:

p = &a[0];     // This is 'H'

Well, one way to find out.... TRY IT!

Really, it harms nothing to try little experiments like this...

Really? I imagined my computer blowing up!

I like the Alt-F4 Windows Aptitude Test; what is crazy is that I learned that function today at my work (some engineer did it, so I inquired how).

The OS will not let a simple program error blow it up. You may get seg-faults or access violation errors, or your program may crash in some very inglorious way... but except in extreme situations (most often as the result of deliberacy) one blown-out program will not crash a system.

IOW... what do you think error messages are for? That's your system protecting itself.