Finding MAX or MIN within a string

I am new to C, just experimenting few things. I am trying to find the maximum number or the last number within a string, exp: if I entered 1234 I should get 4 back, but the code below returns the whole thing: 1234

Is there a function (maybe called "MAX") I can use to retrieve the last number whithin a string?

Thanks for your input in advance.

-Dale
dba@datah.net

Code:

#include <stdio.h>
#include <string.h>
main()
{ 
	int a, i, j;
	char x[100];
	
	printf("Please give me a string: ");
	scanf("%s",x);
	printf("\n");

	i = 0;
	while (x[i] != NULL)
	{
		x[i] = x[i];
		++i;
	}
	
	printf("The maximum number within this string is %s ",x);
}

How about :

Code:

#include <stdio.h>

int main(void)
{
  char  buf[] = "1234";
  int i;
  
  for (i = 0; buf[i] != '\0'; i++)
  {
  }
  
  i--;
  
  printf ("Last character in string is %c\n", buf[i]);
  
  return(0);
}

Code:

#include <stdio.h>
#include <ctype.h>

int main(void)
{
  char  buf[] = "1234";
  char max = 0;
  int i;
  
  for (i = 0; buf[i] != '\0'; i++)
    max = ( isdigit( buf[ i ] ) && buf[ i ] > max ? buf[ i ] : max );
    
  printf ("Biggest character in string is %c\n", max);
  
  return(0);
}

Code:

#include <stdio.h>
#include <string.h>

int main (void)
{
  char max='\0', min='\0';  /* Initalized them to characters thate the user can't input */
  int len, count;
  char buff[20];

  scanf("%s", buff);

  len = strlen(buff); /* How long is the string */

  for (count=0; count<len; count++) /* Step through the string */
  {
    if ( buff[count] < '1' || buff[count] > '9') /* If the characters are not between 1 and 9 then skip them */
      continue;

    if (max == '\0')
    {
      max = min = buff[count]; /* if max is still the inital value then assign the character to min and then to max */
      continue; /* skip the rest of the loop and go on to next character */
    }
    if ( max < buff[count] ) /* If max is lower then the character its no longer the max */
      max = buff[count];
    if ( min > buff[count] ) /* if min is greater then the character its no longer the min */
      min = buff[count];
  }

  printf("The max and min of %s is %c and %c\n", buff, max, min);
  return 0;
}

max = ( isdigit( buf[ i ] ) && buf[ i ] > max ? buf[ i ] : max );

You trying to kill the poor kid XSquared?

Hey, it works. (I think)

Thank you guys for your prompt response.

I see that you hard coded 1234, but instead, I'd like to ask for the user input, he/she can enter any numbers from 1 to 9, the pgm should retrieve the MAX based on the input from the user..

Thank you again.
-Dale

Thantos, your code worked beautifully, it is way to cool

Thank you everyone for your help, this is a cool Forum, I will let all my friends know about.. You guys rock!

-Dale

Remember its more important to know how it works then just having it worked.

>>I am trying to find the maximum number or the last number within a string
This is two different requirements. Which is it your after doing?

Code:

int main( void )
{
    char buf[BUFSIZ] = {0};
    char *p[10] = {0};
    int x;

    printf("Enter a string containing digits: ");
    fgets( "%s", BUFSIZ, stdin );

    for( x = 0; x < 10; x++ )
        p[x] = strrchr( buf, '0'+x );

    for( x = 9; x > -1; x-- )
        if( p[x] )
        {
            printf("%c is the highest digit in your string.\n", '0'+x );
            break;
        }
    if( x < 0 )
        printf("There were no digits.\n");

    return 0;
}

You could do the same thing but do some pointer comparison to see which one occurred last.

Quzah.