simple c question

i have one set of numbers many numbers start with '1' and start with '2' and start with '3'. i seperate these numbers how i identified which numbers start with '1','2' and '3'?

Well if you read them in as strings, then you do

Code:

if ( num_in_a_string[0] == '1' )

Or...

Code:

if( strchr( num_in_a_string, '1' ) == num_in_a_string )

Next poster, come up with your version of it.

Quzah.

Probably :

Code:

if( strchr( num_in_a_string, '1' ) == num_in_a_string )

unless he wants to find SOH

*slaps forehead* Yeah. I should have just used the strstr version. That's what I get for not having some coffee right when I get up. Be right back.

Quzah.

Without using any functions prototyped in string.h!

Code:

#include <stdio.h>

int main(void)
{
  int num = 123984;
  int i;
  int is_a_one = 0;

  for(i = 1;i < num && i > 0;i *= 10)
    if(num/i < 10)
    {
      if(num/i == 1)
        is_a_one = 1;
      break;
    }

  printf("It's%s a one!\n", is_a_one ? "" : " not");

  return 0;
}

Without weird nested ifs

Code:

#include <stdio.h>

int main()
{
  int num = 123984;
  int i;
  int last_digit;

  while(num > 0) {
    last_digit = num % 10;
    num /= 10;
  }

  printf("Number starts with a %i.\n", last_digit);
}

Code:

if ( num == 1 || ( num >= 10 && num <= 19 ) || ( num >= 100 && num <= 199 ) )

Just add the other half-dozen or so cases and you'll have all the numbers which begin with a '1'

Code:

int first_digit(int number)
{
        if (number < 0)
                number = -number;

        while (number >= 10)
                number /= 10;

        return number;
}