Thread: Recursive function and segmentation fault

Hello all,

I am new to C programming and I am currently working an encoder program that encodes text unintelligibly. I need help writing my recursive function to provide the desired output results. A sample is below. Can anybody help me out or point me in the right direction or even tell me what I'm doing wrong?

Also note this program was written using Netbeans 6.9.1 with the Cygwin compiler. When I run my program on the school server, 'which is probably an older compiler', I get a segmentation fault.

What its supposed to look like:
Please enter a line of text. Enter a new line to complete entry.
Hello how are you

The encoded text is:

ouyed reaed owhed elloHed


My output results:
Please enter a line of test. Enter new line to complete.

Hello how are you
word count:0 elloedH
word count:1 owedh
word count:2 reeda
word count:3 ouedy
ouedy reeda owedh elloedH

This is a rough draft of my code.

Code:

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

#define LEN_SENT 100
#define LEN_WORD 90
#define NUM_WORDS 50
#define REV_WORDS 40

/* function prototypes */
void encode( char *, char * );

int main()
{
    /* variable and array declarations */
    char string[ LEN_SENT ];
    char *x;
    char word[NUM_WORDS][ LEN_WORD ];
    int i, j;

    printf( "Please enter a line of test. Enter new line to complete.\n\n" );

    fgets(string, LEN_SENT, stdin); /* read the line of text */

    //printf("%s\n", string);

    i = 0;
    x = strtok(string, " -\n");
    while (x != NULL) {
       encode ( word[i], x );
       printf ("word count:%d %s\n", i++, word[i]);
       x = strtok(NULL, "-\n ");
    }
    for (j = i-1;j > 0; j-- ){
    //for (j = 0;j < i; j++ ){
    	printf(" %s ", word[j]);
    
    } /* end for */
    printf ( "%s\n", word[0] );

    return 0;
} /* end main */

/* funtion encode */
void encode( char *dest, char * src)
{
  char *suffix = "ed";
  strcpy( dest, src+1 );
  strcat( dest, "ed" );
  char *temp = "x";
  temp[0] =*src;
  strcat( dest, temp );

} /* end function encode */

On the school server:


./a.out
Please enter a line of test. Enter new line to complete.

Hello how are you
Segmentation fault

Code:

  char *temp = "x";
  temp[0] =*src;

That's not allowed. String literals are immutable. Try this instead maybe:

Code:

  strncat( dest, src, 1 );

What if you just did this then?

Code:

void encode( char *dest, char *src )
{
  sprintf(dest, "%sed%c", src + 1, *src);  // Or is it "%s%ced"? I'm a little confused about where you want the "ed" given your first examples.
}

Note: This isn't a recursive function like you originally indicated you had/wanted, but neither was yours.