Thread: how to merge two arrays recursevly..

i cant understand your question?

what do you mean by
"cant do"

Originally Posted by transgalactic2

i cant understand your question?

what do you mean by
"cant do"

I mean stuff like it can't call external function like isalpha() etc.; can't use globals, why not?? they aren't external functions.

Originally Posted by laserlight

Global variables are unnecessary here. In fact, global variables may complicate the recursion.

they can be helpful to keep track of array indexes since it seems like that the OP doesn't wanna use pointer and offsets.

i need to use the signature that i was given
i am allowed to use pointers
i am not allowed to use global variables

what is the next step??

Originally Posted by laserlight

Why would global variables be useful in the first place? Pointers are already involved.


No, they just make the array indexes harder to track.

maybe not for the input string literals, but for storing 'em in the array result[].

Originally Posted by transgalactic2

i need to use the signature that i was given
i am allowed to use pointers
i am not allowed to use global variables

what is the next step??

point noted and thanks for clarifying.

Originally Posted by laserlight

What do you mean?

figured it was easy to store string literals, str1 / str2 into result[], otherwise after storing str1 the op has to find its NULL before appending str2 into result[]. just my 2c.

Originally Posted by laserlight

Eh, but as you rightly pointed out, this is about merging, not concatenation. result will be filled char by char as the two input strings are recursively traversed. There would be no need to find the terminating null character of str1 after it is stored since it can be retrieved immediately using either the index (or the pointer, as the case may be).

imho the confusion is caused by using same terms for two different things; the op was trying to simply put two functions together and make it into one big function; and in my last post i was referring to the fact that str1 and str2, after they have passed all checks, are combined together to form one big string and stored in result[]; did i manage to cause even more confusion now

this is my try of the unified

i dont know where to merge them ??

Code:

#include <stdio.h>
int merge_strings(char str1[], int index1,char str2[],int index2, char result[], int index3);
int main() {
    char input[255];
    char input2[255];
    char result[510];
    int index,flag,ch;
    printf("enter the first string \n");
 for (index = 0; index < 254 && (ch = getchar()) != '\n' && ch >=0; ++index)
    {
        input[index] = ch;
    }

    input[index] = '\0';

    printf("enter the second string \n");

 for (index = 0; index < 254 && (ch = getchar()) != '\n' && ch >=0; ++index)
    {
        input2[index] = ch;
    }

    input2[index] = '\0';

    flag=merge(input,0,input2,0,result, 0);

    if (flag)
    {
        printf("%s is valid.\n",result);
    }
    else
    {
        printf("%s is invalid.\n",result);
    }

return 0;
}


int merge_strings(char str1[], int index1,char str2[],int index2, char result[], int index3)
{
    int check,check2,check3,check4;
    if ((str1[index1]=='\0') && (str2[index2]=='\0'))
    {
        result[index3] = '\0';
        return 1;
    }
     
 if (((str1[index1]<'a')||(str1[index1]>'z'))&&((str1[index1]<'A')||(str1[index1]>'Z')))
{
        if(str1[index1]<=str1[index1+1])
        {
            return 0;
        }
}
else
{
    
 check=merge_strings(str1,index1+1,str2,index2+1,result,index3+1);
    
}
}//end function

what to do if
one string is shorter than the other
??

Originally Posted by transgalactic2

what to do if
one string is shorter than the other
??

IMO you are trying to fix too many things at the same time. If you find that there are too many things out-of-whack in your program, start from scratch and this time codify merge_strings() so that both tasks (checking if input is alphabetic / ascending and storing the output in the array result[]) are performed in the same function. Just my 2c.