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Using a variable as an array's index?

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Join Date: Mar 2005

Posts: 2

Reputation: duner is an unknown quantity at this point

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duner

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Using a variable as an array's index?

Mar 30th, 2005

Hey all,

First post here and hello to everyone.

I've been studying C for a few months now, and everythnig has been making sense and I'm enjoying the challenge of learning to progeam.

Ther is one thing that keeps eluding my understanding of arrays, and that's using a variable in a for loop such as this:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
 
int main()
{
    int array[10];
	int i;
 
	for (i = 0; i < 10; ++i){
	array[i]=i;
 
	printf("%d\n", array[i]);
	}
	return 0;
	}
#include <stdio.h>

int main()
{
    int array[10];
	int i;
		
	for (i = 0; i < 10; ++i){
	array[i]=i;
	
	printf("%d\n", array[i]);
	}
	return 0;
	}

No matter how I look at this, I can't seem to grasp the function of the variable i in this bit of the code, array[i]. I can see that the loop runs up to 9, that the value of i is being assigned to each element in the array as the loop runs, that the variable i is being used as the index for the array, but why is the i in the array[i] part?

Apologies if this is so basic, but it's driving me mad. Strange thing is, I find pointers to be easier to grasp tham this one thing. lol

Cheers.

Last edited by duner; Mar 30th, 2005 at 2:22 pm. Reason: code formatting

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Join Date: Apr 2004

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Dave Sinkula Dave Sinkula is offline

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long time no c

Re: Using a variable as an array's index?

Mar 30th, 2005

Sometimes you just have to look at something for a while before it clicks. Adding extra printf statments can sometimes help to see what is going on.

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#include <stdio.h>

int main(void)
{
   int i, array[10];
   for ( i = 0; i < 10; ++i )
   {
      array[i] = i;
      printf("array[%d] = %d\n", i, array[i]);
   }
   return 0;
}

/* my output
array[0] = 0
array[1] = 1
array[2] = 2
array[3] = 3
array[4] = 4
array[5] = 5
array[6] = 6
array[7] = 7
array[8] = 8
array[9] = 9
*/

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