>1. If row and col wasn't being initialized was it being Declared?
Defined, actually. But declarations and definitions can be tricky. A definition is always a declaration, but a declaration is not always a definition.

In C it gets so confusing that a definition may look like a definition but still only be a declaration. However, you can save learning that until you want to consider yourself an expert in C.

>2. and why is it that row and col wasn't initialized, but rptr is?
Because row and col aren't assigned an explicit value while rptr is (through malloc's return value).

>3.
malloc returns a block of memory. Memory is just a bunch of bytes all stuck together, and malloc returns a block of N bytes where N is a value that you pass to it. Assuming COLS is 10 and sizeof ( int ) is 4, you would be asking for 400 bytes, or 10 * 10 * 4. malloc doesn't care how you use the memory, it returns the equivalent of a pointer to unsigned char. When you assign the block to a pointer of type int, you can treat the memory as a sequence of 100 integers, or 10 * 10 because even though an int is 4 bytes, we're now treating it as a single unit.

The same thing would happen if rptr were of type double. Assuming sizeof ( double ) is 8, you would be allocating 800 bytes, but still treating that block as a sequence of 100 units (this time of type double).

>4. Is my understanding of how a nested for loop works correct?
You're overcomplicating things. The outer loop executes the inner loop. So if the inner loop initializes one row, the outer loop initializes all of the rows.

>if you don't give it an integer value your program could start acting up?
If you don't return a value then you've invoked undefined behavior, and that's bad. However, the rules are different depending on what version of C or C++ you're using.

>is int main(void) kind of an exception to the rule where a value ISN'T needed therefore
No, don't confuse parameters with return values. int main(void) simply means that main takes no arguments, but it still must return an integer.

Regarding parameters and return values: would an example like this help distinguish the two?

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C++ Syntax (Toggle Plain Text)

#include <stdio.h>
 
int lengthof ( const char *parameter )
{
   int len = 0;
   while ( parameter[len] != '\0' )
   {
      ++len;
   }
   return len; /* len is the return value */
}
 
int main ( void )
{
   const char text[] = "a text string";
   int length = lengthof ( text ); /* text is the argument to lengthof */
   printf ( "the string \"%s\" has a length of %d\n", text, length );
   return 0;
}
 
/* my output
the string "a text string" has a length of 13
*/

#include <stdio.h> int lengthof ( const char *parameter ) { int len = 0; while ( parameter[len] != '\0' ) { ++len; } return len; /* len is the return value */ } int main ( void ) { const char text[] = "a text string"; int length = lengthof ( text ); /* text is the argument to lengthof */ printf ( "the string \"%s\" has a length of %d\n", text, length ); return 0; } /* my output the string "a text string" has a length of 13 */

If you write a function to count the characters in a string (as above), you'd probably pass a pointer the string and return a count of the number of characters.

If write a cube root function, you'd probably pass some value, calculate the cube root, and then return the result.

The parameter(s) is what the function gets to do whatever it is the function does. The return value is whatever the value returns. The relationship between the two depends on what the function does.

Hello,

I see a problem with the following code:

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int main(void)
{
myfunction(argument1, argument2);

int argument1 = 4, argument2 = 5;

return 0;
}

int main(void) { myfunction(argument1, argument2); int argument1 = 4, argument2 = 5; return 0; }

Simple. You create your variables after you try and pass them to myfunction(). Rather, your code should be:

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int main(void)
{
int argument1 = 4, argument2 = 5;

myfunction(argument1, argument2);

return 0;
}

int main(void) { int argument1 = 4, argument2 = 5; myfunction(argument1, argument2); return 0; }

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