expanding function

Write a function expand(s1,s2) that expands shorthand notations like a-z in the string s1 into the equivalent complete list abc...xyz in s2 . Allow for letters of either case and digits, and be prepared to handle cases like a-b-c and a-z0-9 and -a-z . Arrange that a leading or trailing - is taken literally.

How exactly am i supposed to handle a-b-c? Just print out abc?

And what about z-a. Should i print thise backwards, from z to a?

How about handling -a-z, how to handle this?

Quote:

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Originally Posted by Tool

How exactly am i supposed to handle a-b-c? Just print out abc?

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Ask your teacher what "a-b-c" means. Certainly, printing out "abc" is one option, but another option is to regard it as an error.

Quote:

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Originally Posted by Tool

And what about z-a. Should i print thise backwards, from z to a?

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Again, ask your teacher what "z-a" means. It makes sense to print the letters from z to a in that order, but it could also make sense to print them from a to z, or to regard it as an error.

Quote:

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Originally Posted by Tool

How about handling -a-z, how to handle this?

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You could just check to see if the first (and/or last) character is a dash.

Well i wish i had a teacher, im just self studying from the C book.

I did write the code for this, based on another code i found and its output looked like this - see attachment.

Anyway, this is the code i wrote...

Code:

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#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 1024

void expand (char dest[], char s[])
{
    int x = 0, y, z = 0;
   
    while(s[x] !='\0')
    {
        if((x == 0 || s[x+1] == '\0') && s[x] == '-') /* first or last char is a dash */
          dest[z++] = s[x];
         
        else if(s[x] == '-')
        {
            if(s[x-1] >='0' && s[x-1] <='9')  /* checking left char */
            {
                if(s[x+1] >='0' && s[x+1] <='9') /* checking right char */
                {
                      if(s[x-1] < s[x+1])
                      {
                        for(y = s[x-1]; y <= s[x+1]; y++)
                        dest[z++] = y;
                      }
                      else if(s[x-1] == s[x+1])
                      dest[z++] = s[x-1];
                      else
                      {
                          for(y = s[x-1]; y>= s[x+1]; y--)
                          dest[z++] = y;
                      }
                     
                }
                else if((s[x+1]>='a' && s[x+1] <='z') || (s[x+1]>='A' && s[x+1] <='Z'))
                printf("Mismatching argument to expand.\n");
                else dest[z++] = s[x];
            }
            else if(s[x-1] >='a' && s[x-1] <='z')
            {
                  if(s[x+1] >='a' && s[x+1] <='z')
                  {
                      if(s[x-1] < s[x+1])
                      {
                            for(y = s[x-1]; y<=s[x+1]; y++)
                            dest[z++] = y;
                      }
                      else if(s[x-1] == s[x+1])
                      dest[z++] = s[x-1];
                      else
                      {
                          for(y = s[x-1]; y>=s[x+1]; y--)
                          dest[z++] = y;
                      }
                  }
                  else if((s[x+1] >='0' && s[x+1]<='9') || (s[x+1]>='A' && s[x+1] <='Z'))
                  printf("Mismatching argument to expand.\n");
                  else dest[z++] = s[x];
            }
            else if(s[x-1] >='A' && s[x-1] <='Z')
            {
                  if(s[x+1] >='A' && s[x+1] <='Z')
                  {
                      if(s[x-1] < s[x+1])
                      {
                              for(y = s[x-1]; y<=s[x+1]; y++)
                              dest[z++] = y;
                      }
                      else if(s[x-1] == s[x+1])
                      dest[z++] = s[x-1];
                      else
                      {
                          for(y = s[x-1]; y>=s[x+1]; y--)
                          dest[z++] = y;
                      }
                  }
                  else if((s[x+1] >='0' && s[x+1] <='9') || (s[x+1] >='a' && s[x+1] <='z'))
                  printf("Mismatching argument to expand.\n");
                  else dest[z++] = s[x];
            }
            else dest[z++] = s[x]; /* a leading -, just put it in the string */
        }
        else if(s[x+1] == '-') /* check if leading dash */
        {
            if((s[x] >='0' && s[x] <='9') || (s[x] >='a' && s[x] <='z') || (s[x] >='A' && s[x] <='Z'))
            ;
            else dest[z++] = s[x];
        }
        else if(s[x-1] != '-' && s[x+1] !='-')
          dest[z++] = s[x];
     
        x++; 
    }
    dest[z] = '\0';
}

   
   
   
int main(int argc, char *argv[])
{
   
    char s[MAX_SIZE] = "-r-a--";
    char destination[MAX_SIZE];
   
    expand(destination, s);
    printf("%s", destination);
   
    putchar('\n');
    system("PAUSE");   
    return 0;
}

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