I think I need some notation explained :( (if statements)

[zdream8]

I've gotten really confused about this... Below is a simple program I was messing with trying to fix my problem. ...Which I guess is in the if statements. The first "if" is fine...it prints out the first 10 numbers if the array. I want the second if to print out the second set of 10 numbers, but it prints out the first 20 instead...
The third is fine now, but at first I had
if(i<=20, i<30); which gave the same problem as with the second if - all 30 numbers were printed out instead of the third set of 10. Why is that different than
if(i<30, i>=20), which works?

Thanks.

#include <stdio.h>

main()
{
      int i;
      double array[30];
      
      for(i=0; i<30; i++){
               array[i]=i;
               }
               
      for (i=0; i<30; i++) {
          if(i<10){
                   printf("111 %e\n", array[i]);
                   }
          if(i>=10, i<20){
                    printf("222  %e\n", array[i]);
                    }
          if(i<30, i>=20){
                         printf("333   %e\n", array[i]);
                         }
                         }
          getchar();
}

[tabstop]

Comma does not mean "and". "&&" means "and".

[zdream8]

Ack, I was thinking the comma was the problem, but then....oh...so the last on works just because of the i>=20. I get it now... :S
Thanks.