Thread: Expand nightmare!

So here today I am writing this code that will expand on the test string I have created ie. a-f which will write out abcdef. I have most of my logic hopefully correct but the debugger hates my expand call function.
I was wondering what I am doing wrong, because it really hates me and I have been trying to fix it and can't seem to understand what is going on.
I have read on the arrays section and I thought i knew what I was doing......

At last here is my code any help on my expand function would be very appreciated.

Code:

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

char s[100];
int j;
void expand(char from, char to)

main()
{
    char s[]="this is a-f test";
    int len = 16;
    int i;
    
    for (i=j=0; i < len; i++)
    {
        if (isalpha(s[i]) || isdigit(s[i]))
        {
            if (s[i+1] =='-')
            {    if (isalpha(s[i]) && isalpha(s[i+2] && s[i] < s[i+2])
                
                    expand(s[i],s[i+2]);
                
                else if (isdigit(s[i]) && isdigit(s[i+2] && s[i] < s[i+2])
                
                    expand(s[i],s[i+2]);
                
                else 
                    printf("invalid statement\n");
            }
        }
    }
    else
        s1[j++]=s[i];
}



void expand(char from, char to)
{
    char c = from;
    
    while (c <= to)
        s1[j++]=c++;
}

So after a week of redoing this program im so close but I still am having trouble with my expand function I can get it to process the char, but still wont expand it maybe I have it wrong idk can someone take a look and guide me in a direction?

basically your type in like a-f or 1-4 and it will expand to output abcdef or 1234

Code:

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


void expand(char s1[], char s2[]);
int getline(char s1[], int lim);

int main(void)
{
    char s1[100];
    char s2[100];
    getline(s1, sizeof(s1));
    expand(s1,s2);
    printf("%s\n %s\n", s1, s2);
    
     return 0;
}



void expand(char s1[], char s2[])
{
    
    int j, i;
    int len = strlen(s1);
    
    for (i=j=0; i < len; i++)
    {
        int processed = 0;
        char from = s1[i];
        char to = s2[i+2];
    
        if (s1[i+1] =='-')
            if ((isalpha(from) && isalpha(to))||(isdigit(from) && isdigit(to)))
            {
                while (from <= to)
                {
                    s2[j++]=from++;
                    processed = 1;
                }
            }
            if (!processed)
                s2[j++] = s1[i];
            s2[j] = '\0';
    }
}

int getline(char s[], int lim)
{
    int i, c;

    for(i=0; i < lim-1 && (c=getchar()) != EOF && c!='\n'; ++i)
        s[i] = c;
    if (c == '\n')
    {
        s[i] = c;
        ++i;
    }
    s[i] = '\0';
    return i;
}

On this line of code, when i is on it's last loop, what will i+1 be referring to?

Code:

if (s1[i+1] =='-')

You're out of bounds. Check for the hyphen behind i, instead of ahead of it, perhaps.
Or, use a flag, so you never check past the array's bound. When you reach the hyphen, you set the flag, and never check for the hyphen again.

Show me your expected input, and your output example from it. It's hard to believe you need half this amount of code to print up a-f or 1-4, even considering your limit variable.

A=abcdef limit 6
1=1234 limit 4
B=?
20=?

well im trying to do for my input a-f, I thought i got through it by looping the string with either a 1 or 0 as processed or not, it will run through the entire string until it has processed all the characters. so I do not understand what you are saying tater when you say that it will print up to the expand then end the string... maybe I am not that familiar with what you are trying to say i guess?

With my i+1 I am checking each char to see if it has a '-' after each char, if it does not have a '-' it gets marked with a 0 and gets thrown in the j string and keeps going, I thought that after the expand it still would keep going until it runs out of characters.

It will... but you will end up with 0s in your j string... cstrings are 0 terminated... The string will end with the first 0 you put in there.

Also, at no time do you actually insert the expanded list of characters...

Do you think I should put a different number for the character if it is not have a - in front of it? Also can you explain more on the insert the expanded list of characters?? I'm confused by what you are saying?