Thread: scrambling words but leaving the first and last letters in the same position

Hello Everyone,
I writing up a program for a class assignment that will create scrambled words by circularly rotating the middle characters of each word by 1 character. Place the scrambled words, 1 per line in an output file.

in my dict.txt file placed the following words

computer
dog
pepper
marker
teapot

the output file for scramble.txt is the following

ctmpouer
odg
pepper
kaemrr
toaept

the first issue i have is that i can't get to display the output file when i run the program and the scrambling is not working as intended. would i be able to get some help on perfecting this assignment. thanks

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h> /* needed to use exit(1) */
char* scramble(char* str)
{
        int i,m,k;
        for(i=1;i<(strlen(str)-1);i++)
        {
                m = rand() % (strlen(str)-1);
                k = rand() % (strlen(str)-1);
                if(m == k)
                {
                        i--;
                        continue;
                }
                char temp = str[k];
                str[k] = str[m];
                str[m] = temp;
        }
        return str;
}
main()
{
char word[80];
FILE *fpin;
FILE *fpout;
/* open the input file -- quit if not found */
fpin = fopen ("dict.txt", "r");
if (fpin == NULL)
        {
                printf("Memmory allocation failed.");
                exit(1);
        }
/* open the output file */
fpout = fopen("scramble.txt", "w");
while (fscanf (fpin,"%[^\n]\n",word)==1)
{
fprintf (fpout,"%s\n", scramble(word));
}
}

Why are using rand()? If you're rotating char's, that is completely non-random.

When you scramble "pepper" using circular rotation of the letters between the first and last letters only, don't you get: "peeppr"?

And what about "dog" to "odg"? I don't grok that.

What i am trying to accomplish is; as long as the first and last letters of each word are in the same place, the middle letters can be arranged in any order, and the words will still be readable.

sample input file:

dog
pepper
marker
teapot

sample output file:

dog
pppeer
mrkear
tapoet

I like using a nested for loop pair. Outer one for the word logic, and inner one for the char logic within the word.

An example:

Code:

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

int main() { //
   int i,j,len,idx;
   char c;
   char words[4][20]={"Ohio","Utah","Montana","Vermont"};

   for(i=0;i<4;i++) {
      len=strlen(words[i])-2;
      for(j=1;j<len;j++) {
         idx = j;
         while(idx==j)
           idx=rand() % len+1; //printf("j: %d  idx: %d ",j,idx); //getchar();
         
         //swap
         c=words[i][j];
         words[i][j] = words[i][idx];
         words[i][idx] = c;      
         //printf("%s\n",words[i]); getchar();
      }
   }

   for(i=0;i<4;i++)
      printf("%s ",words[i]);

   printf("\n");
   return 0;
}