Ttykuu

I'm posting this there and not on SO because i can't find any error despite having messed around with gdb and valgrind, but it's likely that there's a memory violation or undefined behavior somewhere .

This is my submission for this problem : I have to cipher a given string using Caesar's cipher, cut it into 5 substrings , put them into an array and return the array.

Then i have to implement the reversed process .
My program seems to generate non printable characters when run by the site.
It runs fine on my machine but the problem is certainly on my side.

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



/* computing the size of every string and putting these 
 * sizes in the array */ 

void five_parts (unsigned* array ,size_t number) 
 unsigned div5= number/5 ;
 unsigned mod5= number%5 ;
 unsigned i ;
 if (mod5==0)
 for (i=0;i<5;i++)
 array[i]=div5 ;
 else 
 unsigned remainder =number-4*div5 ;
 for (i =0;i<4;i++) 
 array[i]=div5 + (remainder>0) ;
 if (remainder>0)
 remainder--;
 array[4]= remainder ;



/* encrypting a string , without mutation 
 * returns a pointer to the encrypted string 
 * the shift is incremented at every character */

char * encrypt ( char * string,int shift ) 
 char * encrypted =NULL ;
 size_t i, length= strlen(string) ; 
 if (!(encrypted=malloc((length+1)*sizeof(char))))
 exit(-1);
 encrypted[length]=''; 
 for (i=0;i<length;i++) 
 shift%=26 ;
 if (string[i] >='a' && string[i] <='z') 
 encrypted[i] = (string[i] +shift>'z') ? string[i] +shift-26 : string[i] +shift;
 else if (string[i] >='A' && string[i] <='Z') 
 encrypted[i] = (string[i] +shift>'Z') ? string[i] +shift-26 : string[i] +shift;
 else 
 encrypted[i] = string[i] ;
 shift ++ ;

 
 return encrypted ;


/* decrypting a string , without mutation 
 * returns a pointer to the decrypted string */ 

char * decrypt ( char * string,int shift ) 
 char * decrypted =NULL ;
 size_t i, length= strlen(string) ; 
 if (!(decrypted=malloc((length+1)*sizeof(char))))
 exit(-1);
 decrypted[length]=''; 

 for (i=0;i<length;i++) 
 shift%=26 ;
 if (string[i] >='a' && string[i] <='z') 
 decrypted[i] = (string[i] -shift<'a') ? string[i] -shift+26 : string[i] -shift;
 else if (string[i] >='A' && string[i] <='Z') 
 decrypted[i] = (string[i] -shift<'A') ? string[i] -shift+26 : string[i] -shift;
 else 
 decrypted[i] = string[i] ;
 shift ++ ;

 
 return decrypted ;



/* creates a string array containing 5 strings ; 
 * ciphers the input string without mutation, cut it into 5
 * parts , and returns a pointer to the string array */

char** movingShift (char* strng, int shift) 
 if (!strng)
 return NULL;
 unsigned i,j ;
 size_t length=strlen(strng);
 unsigned sizes[5];
 five_parts(sizes,length); 
 char ** array ;
 if (! (array=malloc(5*sizeof(char*) ) ) )
 exit (-1) ; // allocation error
 char * encrypted,* ptr ; 
 encrypted=encrypt(strng,shift);
 ptr=encrypted;


 for (i=0 ;i<5;i++) 
 if (!(array[i]=malloc(1+sizes[i]*sizeof(char)))) 
 for (j=0;j<i;j++) //freeing the previous ones
 free(array[i]);
 exit (-1); // allocation error

 array[i][sizes[i]]=''; //NULL terminating
 strncpy(array[i], ptr, sizes[i]);
 ptr+=sizes[i] ; 
 
 free(encrypted) ;
 return array ;


/* deciphers the given strings array , 
 * returns a pointer to the deciphered string */

char* demovingShift(char** s, int shift) 
 if (!s) 
 return NULL; 

 size_t length=0 ;
 char * decrypted ;
 char * part ;
 size_t sizes[5] ; 
 for (int i = 0 ;i < 5 ; i++) 
 length+=strlen(s[i]) ;
 sizes[i]=strlen(s[i]) ; 
 

 decrypted=malloc(1+length);
 decrypted[length]='' ; // NULL terminating
 for (int i = 0 ;i < 5 ; i++) 
 part=decrypt(s[i],shift);

 strcat(decrypted,part);
 shift+=sizes[i];
 shift%=26;
 free (part); 
 

 return decrypted ; 



int main () 
 //char * u= "I should have known that you would have a perfect answer for me!!!" ;
 char* u = "-uoxIirmoveNreefckgieaoiEcooqo";
 int shift=2;
 char ** array= movingShift(u, shift);
 char * v =demovingShift(array,shift);
 printf("decrypted:

Any insight greatly appreciated :)