Thread: confusion in array concept...

Code:

  int c,a[10];
  while((c=getchar()!=EOF)
  {
         if(c>='0' && c<='9')
              ++a[c-'0'];
  }

i have a confusion in the body part of while loop .... what does the body part mean??????

that's fine ... i know for array we increment the index for getting the next value...
but over here,
[code]
if(c>='0' && c<='9')
++a[c-'0'];
[\code]
what are we doing over here???
basically as we are writing 0 as a character '0' thus as c is an integer, '0' will be converted into it's ascii value 48 and thus it will be checked in the if condition and similary for '9'.... now when we write ++a[c-'0']
it means a[c-'0']=a[c-'0'] + 1 which i am confused ???
if you could explain it more it would be clear to me....

You are correct that the entered value is in ASCII. That is, digits '0' to '9' are really integers 48 to 57.
The 'if' statement checks that the character is within that range. You could have done it this way as well: if (c >= 48 && c <=57) but using the quoted chars is easier to read.

The c-'0' calculation removes that offset. We know '0' is 48, or you could have written it as c-48. It ensures the index becomes 0 to 9.

thanks...
got it...